0 Population units unable to be created above pop limit

So I tried making a mod where I have unpacking units as buildings. They cost 0 pop and 0 pop-headroom and can be created when there is available headroom or 0 headroom. If however I go above the pop limit such as 6/5 population then these unpackable units will not finish creating due to the population limit being reached even though they cost not population or headroom. Has anyone experienced this issue or discovered a workaround?

probably hard coded, came across similar thing too.