How are you moving a building to an occupied spot? What building are you moving / what is occupying it? If you could grab a screenshot that might explain it even better.
I'm trying to switch position between the embassy and the two huts left of it.
Starting position:
Moved one hut and the embassy, the second hut is highlighted in green (so everything looks fine)
Place building, highlight disappears, but building isn't placed
Highlight in blue like there is another building beneath, but you should be able to place it
Highlight back to green
Reset after third try. May also result in an error message and forced refresh.
Funny thing: I just discoverd that when you refresh right after 'Place building, highlight disappears, but building isn't placed' it's placed corretly after the refresh.
Edit: and then it all goes wrong again: hut connected by road isn't actually connected and when picking up and replacing the embassy on the same spot it results in the error message and forced refresh.