I’ve organised my series in collections with the use of tags. I did this on the top-level for series.
I delete episodes after watching, and when the last available episode of a series gets deleted, the tags go as well: when a new episode is added to the server the collection-tags are missing.
Can Plex remember my modifications to the tags even if there are no episoded available for some time?
I delete episodes from within Plex, so the series-folder on my pc is never deleted, only individual episodes.