Bug prevents one specific local song from being added to one specific playlist

[DaGuitarPlayer]

Device

PC

Operating System

Windows 10

My Question or Issue

I just downloaded an album to add a specific song from to a Spotify playlist as a local file, which I do all the time. This time, I appear to have stumbled into a bug, however, as the song in question can be added to every single playlist except the specific one i want it on: https://open.spotify.com/playlist/71yjK0kr92IWV1Gk6DqNkH?si=e5b6bda483334414

I have set up spotify to look for local music in my downloads folder, as well as another local music folder. When I first downloaded and extracted the album to my downloads folder, every song became visible in spotify. I then:
1. Added the specific song (myspace.org (FT:TOKYOPILL)) to the playlist.
2. Moved the local song file to the other local folder music folder
3. Deleted all the remaining tracks from the downloads folder.

After these steps, the song is no longer present in the playlist, but still visible and playable from the local files tab in spotify. I can add the song to any other playlist without problem, but when I try to add it to the Loading... playlist, it only appears for a split second before disappearing again. Even if I add it multiple times, I do not get the usual prompt asking if I'm sure I wanna add the same song to the playlist twice. I also have no problems adding other songs to the playlist.

I think a bugged invisible entry for the song with the wrong local path listed is still present in the playlist, which prevents the song from getting added again. Would you be able to detect or remove this bugged entry?

I tried changing the metadata of the song (the title, specifically) but that didn't help.

I could recreate the entire playlist from scratch, but I don't want to lose all the dates showing when I first added the songs to the playlist.

[DaGuitarPlayer]

I just realized that every single other local file added to the playlist isn't visible in the spotify application, and they won't play when they should.

Additionally, I discovered that all the local files are still visible when opening up the playlist on the web, but of course they can't be played there either.

[DaGuitarPlayer · Accepted solution]

It... seems I have somehow resolved the problem, though I'm not quite sure how. I figured out that I could get the local songs to play in the playlist, if i started the playlist through the web browser, while setting spotify to play through the desktop application, and then using the desktop application to select the local song in the queue.

After doing this, the missing songs were suddenly back, and I could add the problematic song to the playlist without problem.