OK, the bug is really that the Auto turn end often ISN'T applied. I shouldn't see a green end turn button when end auto turn is turned on.

What I though a bug was WAD (working as designed.) The real bug is the rest of the system

Original text below.

[BUG][.50]Turn ends prematurely when you try to attack an adjacent unit you can't reach that turn.

There are probably other things that trigger this, but this one is easy enough.

Arrange for the unit (it may have to be the last one with movement left) to be adjacent to a stack and showing a yellow 1, it will end the turn.