Hi guys. I have the same issue which is related to this topic
In that topic, the solution for the Threaded Layout was to simply switch on a setting.
Unfortunately, this applies only to that layout and there are no options to do the same for the other layouts.
Any reason why that is?
Please go to Dashboard > Forums > Settings > Topics & Posts Tab and check that Q&A Layout - First Post Reply Button, Threaded Layout - First Post Reply Button are enabled. Then check the layouts again