Okay, I can confirm that the forum pagination issue is with that plugin: bbPress Threaded Replies.
I have now deactivated that plugin and gone back to a flat forum approach. I’ve looked around a few bbPress quote plugins, but they all seem to have problems with current versions of WordPress & bbPress.
On the other hand, a special quote plugin is not really necessary because the posts all have permalinks, which I really like. For me, it’s easy to just right-click on the post permalink and then paste that link into my own reply if I want to reference a specific person’s post in the discussion. But most of our users would have no clue how to do that without a very specific demo. So, I have two video production students now making some short screencasts which I will embed into a super-sticky post for all forums. Hopefully, these short screencasts will help inexperienced users be more productive in the forums.
Any other suggestions based on your experience?