Josh Petersen

I feel like there was a change in 1.16 that updated the needed light levels for crop growth becuase I had this same issue.  Farms that were growing stopped.. added more lights and they are working again, so not really a bug, but a change did happen.

Yes, it appears the new pathfinding attributes addedin 1.16.2 to mobs and villagers now allows them to pathfind over double carpet stacks or other air block methods.  Not sure if the pathfinding work was intended to 'fix' this mechanic or not, but now mobs on double carpets can pathfind away, and can behave strangely when on top of carpets with air blocks below them. (spinning in circles).  I kind of wish they kept it the old way, as this was a very simple and compact method for both mob proofing and handling villagers (trading halls, etc).

I seem to have encountered this today when playing on my realms server (1.15.2).

I had trapped, then named, then converted a zombie villager to a nice healthy villager, but I forgot to light the space i was keeping him.. I was playing in chunk with him (not 50 blocks away) and a zombie spawned in with him and converted him back to a zombie villager.  I killed the zombie, and checked that he was still named (he was), so I figured I'd come back and cure him later.  Came back and he had despawned.  

I can confirm @Fiopon's issue on the latest snapshot/1.15pre2 build.  seems to happen for me where there is a non full block or empty block adjacent.  you can 'jump over, but walking pushes you back towards the empty or not full height block.