Good work, and many thanks!

Now if only the software managers in Mint and the Steam Deck would just find an update past 1.1.3... -.-

Anyway, cheers!

Is there a consistent way to reproduce?

[ TL;DR edit:

1.0 Try click-and-dragging a song to a different position within a single playlist (while having two or more playlist tabs at the top), and then click on a different playlist's tab.

1.1 There should now be a previously inactive, unselected column option now active. The column does not show up until you click a different playlist tab, but remains if you then switch back the original playlist tab you were just manipulating song orders in.

1.2 The previously unselected column options starting showing up, one per combo-action of [click-drag song + click diff playlist tab], in a consistent order of starting with the option at the bottom of the R-click menu for selecting columns you want active, and working upward from there, always adding the last, previously unselected option. So if you remove a column, it comes back, but if you leave that column, it moves to activating the next previously unselected column at the bottom of the list.

2.0 Everything below is just my original post and how I eventually arrived at that conclusion, in case it helps somehow. ]

Not OP, but have same issue. Try these steps (this may not be the only method or set of actions to cause the issue, but it's the one I've noticed consistently at least):

Step 1. Create two or more playlists (A, B, C, etc)

Step 2. Go to a playlist (whichever, let's say A), then R-click on a song, or select multiple songs and R-click, then select the option to "add to another playlist", and choose a different playlist (B, C, D... again, whichever).

Step 3. Go to the playlist you just added songs to (let's say B). The song or songs you just added to the 2nd playlist should be at the bottom (i.e. unsorted, just stuck at the bottom by default), and you don't want them there, so now L-click a song and drag it to a new position in the playlist.

Step 4. Now click back on playlist A. The unwanted columns should now have appeared out of nowhere unasked for (you may need to scroll horizontally to see them).

Every time I do that, it seems to add the new columns starting from the bottom of the [column R-click menu] you use to select which columns you want, and working its way up, so it seems like I always see "Loudness Range" first, followed by "Integrated Loudness", then "Cue", "Rating", etc...

If it matters, I'm on Linux Mint.

EDIT 1:

I finally decided to do a bit of extra testing, and can narrow things down a bit.

So starting with the above info as pre-testing, let's continue:

• Closed the program & reopened.

• Clicked different playlist tabs - everything looks fine, no unwanted columns, as I'd removed them before closing the program.

• Then, clicked on a random playlist and then clicked and dragged a song to a different position in the playlist order, within the same playlist, not added or moved to a different playlist.

• No unwanted columns within the playlist I just manipulated, BUT, as soon as I click on another playlist, the unwanted column appears, and remains even if I click back on the original playlist I was manipulating.

And again, the unwanted column appears to always be the last, previously unselected option, and each time you [1. click-and-drag a song to a different position, and then 2. click a different playlist tab, and 3. click-and-drag a song again] the next unselected column option gets automatically turned on and appears when you click on a different playlist tab.

I can't reproduce this here.
Is there a consistent way to reproduce?

Can you try to start with a new config file and see if that makes any difference, rename ~/.config/strawberry/strawberry.conf while strawberry is closed, does it then work with the default columns? If yes, can you modify one thing at the time and see if there is a way to reproduce it?