This bug looks really old, from Alpha 7 ( [Alpha 7:180] Worker eating Carpenter’s Saw (Not being promoted - Saw Deleted) ) and I’ve seen it reported other times.
The question is why does it happen regularly for you. I usually can promote the carpenter easily and my UI doesn’t get stuck.
With “promotion window” you mean the class tree right? Or is it the citizen roster?
This is a blocker, they should fix it anyway 