Perhaps for others to check this out there’s a little bit of input missing here …
What exactly does it say in Settings - About Phone - Build number?
Do you use a microSD card in the phone?
If so …
You mentioned the latest big Android update (I guess from Android 5 to 6) … There should have been a choice of whether to incorporate the SD card into internal storage or to leave it as is as external storage. What did you choose?
If the SD card is external storage, where do you play the music from? Internal storage or SD card?
Did you try the hints from the other thread already?