I currently have 3 builder but two of them stay in green and nether Come back to red that cause i can't use them to build something dis i miss something or it's a bug (i have the research center)
The construction of the monsterhall and armory in Aldlyn are currently bugged. Because they finish instantly, the construction team is not reset at the end of the construction timer, which is how it works for other constructions.
It's not possible to restore the construction team automatically in this case, but I added an option in the cheat book in your bedroom to turn all construction teams "available" again for those who suffer from this issue. It'll be available in the next upload.