These problems were caused because I was working on a backup of my actual board, so it had over 2000 members, a lot banned etc. I hadn't tested on a smaller board, and that's what caused most problems, for instance I hadn't taken into account that there might be no banned users, I took for granted that some existed.
lasto provided me access to his test forum, so I performed some tests and changes to my code and the issues seem to be resolved. I'm now going to cache some templates I had forgotten to cache, transfer the plugin changes to my product and then I will update the zip on the first post
You will be informed when the zip is updated with a new post.