@jens I’m sorry if it isn’t clear but my comment is in response to benjamin_glatzeder’s question. It sounds this is happening in a released app and he’s more interested in a quick fix rather than the root cause at this time. Maybe I’m reading into it a bit but it sounds like he’s probably fielding a lot of support issues because nobody likes running out of milk. 
So I was proposing a quick fix. My understanding is he’s re-using documents, delete then un-delete and that’s aggravating the problem. I’m proposing he hides them rather than delete them if he plans on reusing the documents. This probably won’t stop the problem completely but it might buy him some time to look for the root cause. If you don’t think this is a good option I can delete the comment.