Matthew Bazil

I have this issue on Windows 10 for sure (haven't tried on other platforms).  I am however, still able to play on the realm.  It's mostly just annoying.  I do have auto renew and a valid payment method so it shouldn't expire for me.

On my realm, I'm currently experiencing either exactly the same issue or something very similar.  Mobs that are hundreds or even thousands of blocks away from any player do not despawn.  I've seen this occur all over my realm, it's most obvious when someone enters an area moving fairly quickly (such as with elytra or maybe even a minecart or horse).  You'll see, especially easily seen in open areas, zombies and skeletons burning more than half way through the day as the chunks load.  Nether appears to have the same problem.