What gameplay feature is this bug affecting?
Mine

What's the issue? Please include any error messages you receive and as much detail as possible.
I was going through my subscriptions, and marked all as seen. Then suddenly, EVERYTHING disappeared! No more notifications! I literally screamed, because they were important!!!! PLEASE FIX THIS >:l

Any links relating to this bug? For example, if a particular lion is bugging, what is the link to that lion?
.

Any screenshots you can provide us with?
nope

Please provide us with step by step explanation how this bug happened so we can attempt to replicate it. If it's complex, please include screenshots where possible:
I was going through my subscriptions, and marked all as seen. Then suddenly, EVERYTHING disappeared! No more notifications! I literally screamed, because they were important!!!! PLEASE FIX THIS >:l

*Error message, "Removed all subscriptions" Then it had some other stuff- I don't remember