Its about time to solve this issue or make some announcement about it. Ignoring paying users is very counterproductive and will certainly cause a batch of unsubscriptions, including me.
more testing with Nokia Lumia 920
Some of old playlists cannot be change to offline, but when I made same playlist again (mobile or computer) playlist CAN change to offline.
And another thing - if playlist cannot change to offline - I can't delete that from mobile phone.
Thanks for this tip.
I tested this myself and it works.
I agree, this is not a solution. But at least we have a workaround.