Quite a serious bug, well it was for me.

when building a 'once per empire' building (not sure what the name was, A-something for 100% extra research bonus)
I had it top of the list but wanted to delay it until later, so I canceled it.
Problem was, once I double clicked it to delete it vaished from the build list options completely. so I don't have it and can't rebuild...
Not in my system overview, not in the build options, not anywhere!

I also noticed my cryogenic research building (also one of those 'once per empire' buildings) is only in the list of buildoptions of one of my colonies.
I would like to build it somewher else, maybe it needs a special planet? if so I haven't discovered the requirements of this building.

I'm guessing its a bug with the 'once per empire' settings

it reappears next turn again or when you save and reload. It isn't completely vanished but you're right, it needs to be fixed (I'm not sure if it is already in the dev version, anyway).

the cryogenic research building is restricted to certain planet types (see buildings editor in ../bote/data/buildings/ folder to get the needed planet types. hm, I guess it could be written into the building's description, would make it easier for the player .