I’ve noticed that recently Plexamp has been showing Tidal results with the search features even though I don’t have Tidal integration enabled - but the situations where they show up is rather odd, for example it only seems to be happening when there are extremely small strings (e.g. 1 character) in the search field.
For example:
If I search “w”, Tidal results show up for various artists, albums, and tracks, such as Pink Floyd’s “Wish You Were Here”.

If I change the search string to “wi”, the Tidal results are removed, and only results from the current Library are shown. (I’m not really sure why “Year of the Cat” is showing up though)

I suspect this is unintended behavior, because the Tidal results really shouldn’t be showing up unless I’ve enabled Tidal integration. Attempting to navigate to an album / artist for any of the results brings you to a page that loads indefinitely, and attempting to play any of the tracks simply triggers a “playback error”.
The screenshots above are from the Linux version of Plexamp (v4.7.4), but I’ve been able to reproduce the same behavior on iOS.
Update: I’m only able to reproduce this behavior with a few search strings at the moment (e.g. “w” or “k”, but not “b” or “n”), but I’m pretty sure I’ve seen it fairly regularly over the past few weeks with other search strings.