The order management addon is new so it is likely that the refund linkage is not working correctly. I will take a look at it.
The commission reversal should work though. Please enable debug and share the debug content after you perform a refund so I can see what is going on. This post has more info on debug:
https://support.tipsandtricks-hq.com/forums/topic/how-and-when-to-enable-debug-and-what-does-it-do