When a villager is ejected from a minecart by an activator rail, they are not targeting an available honey block as a potential space.  While this was also true in 1.15, it's exaggerated in 1.16.

Expectation: when a villager is ejected, it should be placed in an available space (2 air with surface below) adjacent to the activator rail.

First two sceenshots are 1.16 showing how the test was done and the result.  You can see the villager ends up on top of the slabs, leaving them to wander off.  In the same scenario in 1.15, the villager is left on the activator rail.  In both cases, if the honey block were replaced with any other block, including slime, the villager would be placed correctly.