Not being charged for apple music

I have an apple music student subscription and have had it for about 5 years. At the end of each billing cycle, my subscription does not automatically renew like it used to, and instead expires. In July, this happened and I got a pop up on the music app that my subscription expired and I needed to renew in order to listen. So I did, but I was confused as to why that was the second time it had expired and not renewed. Since then, I’ve gotten no pop ups on the app, however my subscription expired on Aug 1, I have NOT been charged for it since, but I’m still able to listen to everything. Anyone know what’s up? I suppose I cannot complain, but just curious as to what may be wrong. I do have a family group with icloud and an apple music subscription is “being shared” by a member, but it’s a single person subscription (the member sharing it buys the individual $10/m subscription) so it can’t actually be shared among several users; it’s not the family music subscription.