Disconnected from the Realm - Map and Loot Gone

I was on a map (City Square) and I'm about 60% done with it. The game lagged for a bit and then I was logged out. The prompt said I got "disconnected from the realm".

After logging back in, my map portals were gone along with the loot that I got from the same map. I lost the actual map as well.

Anyone else who had this issue before?
How can I prevent this from happening again?

This type of disconnect is server-side, so there is nothing that you can do to prevent it.

GGG will be aware of all of these realm disconnects.