Today I took another look at this and fear your fix maybe only cures the symptoms not the root cause. The situation is like this:
PC1 (WIN10): Added the Del Amitri file to the database. Synced to the cloud. Both songs are correct. Del Amitri song contains Del Amitri PDF. Bright Eyes song contains Bright Eyes PDF. When I connect with the companion app from PC2 to this PC1 everything is fine as well. Bright Eyes contains Bright Eyes PDF.
Code:
09:21:13 - Sende PC-Dateien für Song: Landlocked Blues
09:21:13 - 91187 Bytes der Datei: C:\Users\xxxxxx\AppData\Local\Packages\41730Zubersoft.MobileSheets_ys1c8ct2g6ypr\LocalState\Bright Eyes - Landlocked Blues\Bright Eyes - Landlocked Blues.pdf erfolgreich gesendet
PC2 (WIN10): Synced with the cloud drive. Sync ran without errors. But both songs here somehow contain the Del Amitri PDF. Connecting with companion from PC1 to PC2 shows the same:
Code:
09:25:53 - Sende PC-Dateien für Song: Landlocked Blues
09:25:54 - 106775 Bytes der Datei: C:\Users\joern\AppData\Local\Packages\41730Zubersoft.MobileSheets_ys1c8ct2g6ypr\LocalState\Del Amitri - Driving with the brakes on\Del Amitri - Driving with the brakes on.pdf erfolgreich gesendet
Android device: Synced with the cloud drive. Sync failed because of, as you have found out, invalid path.
So while your fix might have adressed different fault tolerance between W10 and Android the problem of the wrong assigned file is alreay in the cloud sync and must have occured while syncing PC1 to the cloud.
I resynced PC1 to the cloud drive today and after that PC2 and Android both synced ok and now on all three devices both songs are correct.
As a conclusion i think there must be some error situations while syncing to cloud drives that remain unnoticed to the user as the sync is reported successful but leaves the synced data in an inconsistent state that garbles the contents of the songs.