Tamed cats cannot be bred

Seems to work fine for me.

Also cannot reproduce.

I was able to get this bug to happen as well on a multiplayer server. However, in a fresh world on creative, it worked fine. What should I look for that I may be doing differently that is causing it since @Neko cannot reproduce it.

Hey, I have been looking into this bug a fair bit and I have a world where they do this bug 100% of the time when within a certain area. I've been trying to find what in this area is causing the issue. Would you be able to upload your world file where this occurred and the coordinate that it happened at?

I'm encountering the same bug now, so it is reproducible in a sense.

First and foremost, this is not resolved.  I believe you should have a separate status for 'Not able to reproduce' or 'blocked'.  I am assuming no fix was done, since it wasn't repro'd by dev team, so resolved would be plain incorrect (unless of course, I am mistaken and this bug WAS worked on...  In which case I regret to inform you that the fix did not fully work as of 1.16.1)

I am playing on 1.16.1 multiplayer with mods, so this might not be the most reflective, But seeing number of people who still encounter this, I'm pretty sure this is from base game.  I don't think this is resolved, I spent a bit testing to see what I could find.  Found some interesting things, but nothing too conclusive (in terms of WHY this was occurring)

Issue, cats can't breed in certain areas.  (ref: '2020-12-13_04.23.10')
As mentioned by David Harmon, after feeding the raw fish to the cats, they get consumed, and hearts appear.  However, nothing occurs.  A few seconds later, you can feed more raw fish to both cats, and the same thing will occur (as opposed to the usual, much longer time if breeding of cats was successful.)

I tried outside, right in front of my house (ref: '2020-12-13_04.28.59') (first feeding attempt was inside, but on 2nd floor, if elevation might matter) (I don't remember if they followed me immediately after first feeding attempt indoors, but I know later when I tried again, they did not follow me for a while.)  (Actually, remembering my game tonight/this morning, after at least one of my attempts breeding the cats, I remember that they didn't follow me.  After a bit of time, I closed minecraft and restarted for other reason I can't remember.  But when I signed back on, both cats almost immediately teleported to my location)

Because of the first two screenshots, I initially thought it was a half carpet floor thing messing with pathing or something.  I tried 2 things, that both disproved that theory pretty quickly.  First, heres a screenshot of two wolves having no issue breeding on carpet area. (ref: '2020-12-13_04.50.57')

Then I tried to breed the cats in the same area, after removing the carpet from the floor. (ref: 2020-12-13_04.58.09)  Same results as before, with the hearts, the lack of a newborn kitten, and the ability to feed them again after several seconds.  It was here I noticed they didn't actually follow me (I made sure they were not sitting.  Neither were sitting when they were fed the fish.

Here is them not following me immediately out the house. (ref: '2020-12-13_05.00.31')

Here is them not following me at a greater distance.  Bit hard to see in the house, but you'll notice One of them just stares at me.  They're clearly still able to focus on player during this time.

Cats eventually teleported to me, after I swam in the river to hunt more fish.  They teleported to me immediately after I hit dry land, not sure if that was a coincidence, or if something I did broke them out of their  weird bug.
Right outside my house, I fed the cats, and they were successfully bred.  Here's the happy family! (ref: '2020-12-13_05.02.20')

This was a bad screenshot though, since you can't see the house.  Here's one almost immediately after, showing you how close it is to the house.  kitten is still there, just under one of the parents. (ref: '2020-12-13_05.02.26')

I'm not really sure the full details of what F3 is supposed to show, so not sure if I have the screenshots at the right time or anything.  

I'm not sure what causes it, but I do believe something trips up the cat to the point that they don't follow the player.  I am not sure if this is time based, or event based...I'd (very roughly) guess event based since one of the people above me mentioned they had to go to y=11.  I'm assuming, he simply hit a range that was too far for the cats to still be loaded, and therefore they broke out of their loop and was then able to teleport to him

I haven't tested with other mob types in my house, other than wolves (ive done it several times before I even found cats, so that really does seem to work for wolves at least.)

Conclusions I'm making about this:

First, this IS likely an issue that almost certainly does exist, even if it is rare.  I understand I'm playing with mods that could always affect these type of things, but the symptoms match too much with what several people and several tickets have already stated.  Pretty sure this exists in vanilla.

Second, as mentioned by many others, this definitely seems location based.  Still not sure the conditions that would cause it, but I can take screenshot of my local area if that can help track down the issue (If I remember to check this page, and it is responded to quick enough)

Third, the fact that the cats show the hearts, but don't do anything, make me think   that the breeding should have worked, but that maybe the game was unable to place the kitten down in a suitable area for some reason.  The way the cats don't move, I'm thinking it get stuck trying to create the kid, and eventually something breaks them out of that wait or loop or whatever the cats are stuck in.  I am guessing the code in the game for cat breeding cooldown (was it 5 minutes?) is conditional on the kitten actually being born, and not the cats breeding in the first place.

I'm down to test further if you have more information that you think might be useful, during the time I will likely playing in the server anyway.  

Cheers for now,
And good luck.

 
Edit: I think it was mostly raw salmon I used, if that makes a difference.  Might have had raw cod at one point, but I really don't think so.

So, I tested this again this morning.  I am positive this has to do with the cat's pathing movement, and its interest in beds on a different elevation.  Not related to breeding, I noticed my cat got stuck in one particular place in my house (100%).  When Ibroke the block underneath (the carpet, AND the wood plank, the cat landed right on the bed I had underneath, and just rested there.  I also looked at one of the images that were not attached to this ticket by me.  Lo and behold, the cat that can't breed properly looks like it is underneath a bed from upstairs.  (ref: '2020-05-11_14.30.52.png')

I think this ticket is HIGHLY relevant, despite the Mod's comment.  
https://bugs.mojang.com/browse/MC-165629
I'll of course, try to repro this in vanilla now that I have a clear idea of what this might be.
That would make this ticket not a breeding issue, but actually an issue pathfinding towards the bed being broken, and taking priority over other actions (bredding OR following player.  Though, I'm no longer sure what breaks the cat out of this pathfinding.  Makes sense why a decent amount of people would run into this too.  Presumably, most people bring the cats home before trying to breed the cat, which obviously occurs more around beds.

I reproduced this consistently in vanilla.  (I did it with the bed on top and the cat not able to reach.  Pathing to bed gets caught up some times.  Still not sure what breaks cat out of this bug, but I am positive that this is what is interrupting the cat's breeding process.

https://www.twitch.tv/videos/836204156
More importantly, this validates 
MC-165629
as an issue.

For those who follow this ticket as generally interested users, I've created a new ticket, combining both of these issues into MC-208351 in case this particular one never gets updated/seen by devs

Hi Derek.

I just read this in an unofficial Minecraft page (https://www.gamepur.com/guides/minecraft-1-14-cat-tame-breed)

"Sibling cats are also unable to breed."

Could this be your issue?

Regards.