After a while (approx ~1h of game), the building placement is buggy. When you select a building via the menu icon, the building ghost is placed under the initial position of the cursor but doesn't move with it (as it normally do). The position is updated if you left-click on the building itself. Hence, it is impossible to set the building construction as the left-click doesn't respond as it should do.

You still can save & exit. Restarting the game fixes the issue (but it reappears approx 1h later).

I´ve got the same problem - OS: Windows 10.

I did not notice this issue and I've played two sessions of K&C which lasted for about 4-5 hours each. What I DID notice though is that sometimes the building cursor disappears after placing a building (I mean it switches back to the regular - nothing selected mode).

For example, I wanted to build several farms and I had to pick them all from the Food menu individually, since the cursor would revert after each placement.