So, I've been having trouble merging items.
Every time I have a new file for a particular show, it creates it's own category (needs to be match correctly). So I proceed to merge it myself. Except, every time I merge, I always end up with a show that has been incorrectly matched.
Now, I just read this 'Note: The first item you select is what all selected items will be merged into.' from your page (https://support.plex.tv/hc/en-us/articles/201018248-Merge-or-Split-Items) and proceed to select the correctly matched item first and merge with the other. Still the same results.
So, the question is. How do you REALLY merge tv shows?