I won’t be able to access my Xbox for another day or two, but if you need another copy I can also provide one.
@Mega_Spud, I am experiencing virtually the same thing as Theresa to this point. I previously noted a runaway mob spawning in general (legions of mobs in the nether made venturing in there practically impossible).
I am not entirely sure what the specific version name/number was when I converted, but what I can say is that I did the conversion in January of this year, 2018, with whatever the latest version for Xbox One was at the time. I have checked on the map post-other-updates, and the spawner is still empty. This is true for numerous spawners where I've built farms, but keep in mind it was not immediately true when I converted the map. I converted the map and the spawner was working fine, to a point where I worked three or more weeks on the map. At some point, things broke.
I can say that the spawner just down the way in the Nether (my first identified problem was a Nether blaze spanwer) does work. However, that isn't a 'new chunk' per say. I've likely rendered that several times before. I rendered it for the first time on my converted world well after this error, though.
Yet another person having this issue. Xbox world converted over after Better Together update. Converted it roughly on January 15. This world has hundreds of hours of prior gameplay on Xbox One Edition.
I had a barricaded blaze spawner saved up for a long time. Finally I decided to build on it. After numerous painstaking trips after dying countlessly, I finally constructed a blaze spawner farm. The farm worked once... dozens of blazes spawned. For some reason it stopped working. I read everywhere and covered all my bases. It's not a mob cap issue, but I get the impression it might still be related to that. Finally I realized the spawner was 1) not making a clicking sound (i.e. an attempt to spawn) and 2) no longer had a blaze inside it. The blaze spawner down the road was still functioning when I went up to it. I attempted to reset on peaceful and go back to normal, to no avail. The spawner is definitely empty.
Strangely, my world is absolutely flooded with mobs. When I was trying to see if this was a mob cap issue, I had 8 wither skeletons and 3 large magma cubes chasing me, with maybe 4 naturally spawned blazes shooting at me. In my main overworld base, areas that never used to spawn mobs are now getting chickens and llamas and cows everywhere. I walked by the river and there were 6 creepers hanging out in the water and a witch on the shore.
One small final note... back in the nether, ghast sounds don't seem to decrease in volume as I get further from the ghast. It seems that only when they de-render do they stop making noises.
selbram this is different the piston head isnt flat ill add a picture
Happened to me on a Realm