Certain Local Track become corrupt after every upgrade

[Patthesplat]

Hi all,

I have noticed on my iphone 5S, that every time there is an upgrade to the spotify app, some specific local songs in my mixed playlist (spotify tracks and tracks form my Itunes library) become corrupt on my IOS app and will not play.

There are about 40 songs which have this issue, and it's always the same songs that become greyed out in the IOS app and will no longer play.

This will still play on the Windows app no problem.

They were synced from my local Itunes folder.

The only way I can fix this is to dompletely delete these tracks from all playlists, and then add them back again manually one by one.

Once I do that, they work fine, until the next time Spotify rolls out an upgrade, and then they are suddenly greyed out again.

It's reached the point where I have to keep a separate list of these 41 songs because I know they will break every time there is an update.

I can't see any obvious connection between these 40 songs - they include tracks from various artists and albums, so I haven't been able to find a connection why these particular 40 tracks would become corrupt.  In some cases, it looks like I have other tracks from the same album and they are still working fine.

Edit:  Since today it also appears that Spotify have removed the ability to do a search on local tracks from the windows client, so this makes it much harder to re-add these tracks back in again when this issue occurs.

(This is in addition to the separate and well documented issue with mixed local and spotify playlists where playback will "randomly" stop during play of the playlist - separate threads about this issue which has never been solved even though it was reported nearly 2 years ago).

Any help or advice appreciated?

TIA