Date-based TV Show Has Incorrect Organization

I have a bunch of video podcasts that I'm adding to my Plex library. I'm following the guide for adding "Date" based TV shows, found here: https://support.plex.tv/hc/en-us/articles/200381053-Naming-Date-based-TV-Shows

My directory structure is the same outlined in the guide:

Still Untitled
    + Season 01
            Still Untitled - 2012-01-01 - Cars.mp4
            Still Untitled - 2012-01-08 - TV Shows.mp4
    + Season 02
            Still Untitled - 2013-02-03 - Trucks.mp4
            Still Untitled - 2013-02-10 - Cakes.mp4
    + Season 03
            ... episodes from 2014
    + Season 04
            ... episodes from 2015
    + Season 05
            ... episodes from 2016

When I create a brand new "TV" library in Plex, and go into the "Still Untitled" show while Plex is actively doing its initial scan of the directories I've configured for this particular library, I see five seasons: Season 2012, Season 2013, Season 2014, Season 2015, Season 2016. If I wait until the building of the TV library is completely finished (so all metadata processed and artwork has rendered,) and I go back into "Still Untitled", I see four of the seasons remain, but the "Season 2015" season has been renamed to "Specials".

Inspecting the details of a handful of videos from this new "Specials" season and videos from the other seasons reveals no discrepancies in metadata; all of the fields specified for a video in "Season 2014", for example, are also specified for a video in "Specials", and vice versa. The naming convention used across all files in the five directories is consistent.

I'm baffled by this. I'm not sure why "Season 2015" is appearing as "Specials". I also read https://support.plex.tv/hc/en-us/articles/200220707-Naming-TV-Show-Specials-, which didn't reveal anything I might be doing wrong.

It may be worth noting that I'm using the "Personal Media Shows" agent for this TV library.

Does anyone have any thoughts as to what could be happening? Clearly the directory structure is properly read during the first moments of initialization, since I can see all 5 seasons correctly. Something happens during the metadata phase that changes that, but viewing the metadata doesn't reveal anything to me.