Still in 1.14.1
The problem is that the boats are being placed slightly inside the dispenser block and thus they will stay on top of the block underneath the dispenser and its two neighbouring blocks.
I think this could have happend because the hitbox of the boats did change when they reworked them (maybe...?)
I think this bug is actually kind of a feature, because you can use it so widely e.g. for superspeed sprinting tunnels through the nether. It would be a shame if this gets fixed, even though it makes no sense that you could slip on half slabs if there is ice under them.
Confirmed for 1.14.2 pre release 1
still in 1.14.1, should add that to the affected versions
did you update your world from 1.13.2?
If so try optimizing the world and erasing the cache and see if that fixes it
would be quite cool if they would fix this by giving them a different schedule for every dimension, so they would never sleep in the nether and end but instead work more efficient.
Can't confirm this for 1.14.1 pre-release 2. I tested hitting the Zombie with a sword in creative to then kill him in survival by nudging him off a cliff.
I have the same bug on Debian Buster with KDE and Nvidia Graphics Card. I had this bug in 1.14 and also now in 1.14.1 pre-release1
Is this annoying bug going to be fixed soon? It is in every version up to the current 1.15pre4. It is less annoying it seems, but it is still there and still goes away in fullscreen.