Actually I think its a plist issue.
I just pushed a fix to Git a couple of days ago.
Basically its because all OF apps use the same bundle id in their plist and the permissions on 10.14 uses that ID for the camera access.
Try changing the bundle id to:
You might need to do a clean and maybe rename your executable, but then it should only ask once.
I don’t think its related to code signing but there is some discussion here about that: https://github.com/openframeworks/openFrameworks/issues/6310
Hope this works for you.