When playing Malians, this error comes up a lot:
You select a villager and place the blueprints of houses around a Pitmine (or mine).
Holding shift and then pressing QQ, to place the blueprints with only moiving your cursor there and clicking.
After the 5th blueprint, the shift-command always gets cancelled (as well as the selection of QQ) and you have to release the shift-button, press and hold it again and press QQ again to place the houses which exceed the number of 5.
So it seems like this problem always happens when your number of blueprints exceeds 5, for Malian houses.
This sometimes happens for other buildings as well.