This has been happening to me very often on PS4 for at least the past few weeks. I've seen it reported at least a few other times, as well, so it does seem to happen fairly regularly to at least some players. The only workaround I've found is the same as you described -- quit and restart D2. I haven't seen it mentioned in the known issues list for any release, and I've not seen any substantive responses about whether they're aware of an issue, investigating, or if it's at least in the queue of things to look at.