Cloaked colony ships can't colonize!

[Q]

I believe I found the reason why the AI did not uncloak the ships: all ministers were on duty except the "Automatically use Individual Minister for newly built vehicles". As said, using all other ministers the ships did not uncloak for several turns and couldn't colonize the planets. However after turning the empire back to a complete AI player the colonization was successful. I can't repeat it, but probably the effect would have been the same when activating the minister for individual ships.