Some might not call this a bug, but since it creates inconsistency in the game I do
.
The bug can be reproduced on any map with a shipyard.
First, build the shipyard. (obviously)
End the turn.
Build something in the town (doesn't matter what structure).
You can still build a boat. We can conclude that building structures in a town does not affect your ability to make ships.
Move a hero in the boat
End the turn.
Move the boat away to make space for another one.
Build another one.
Then bug. You can no longer build a structure that turn.
So if you want to build both a structure and a boat, you must build the structure first, otherwise if you make the boat first you can no longer build.
If you don't have time to make a map to reproduce this, here is a demo map (it will be deleted in 7 days). It has the shipyard built and enough resources
.
EDIT: Why is the forum breaking the links?
Here it is: https://we.tl/t-VRsB4YOkgk