Updating Server Version Deleted Characters, Can't Access Character Sheets

After updating my Foundry server from 0.7.x (I think 0.7.2) to 0.8.6, when restarting the server almost all of my actors are missing in the actor tab, including all the player characters. They have some tokens on the map but they aren’t linked to an actor any more. I also cannot access the character sheets of any of the actors in the actors tab or tokens on the map.
I’m running Pathfinder 2nd Edition with a few modules.
I was able to change back to version 0.7.2, and all my actors are back and correct. However this seems like it will prevent me from using the newest version of Foundry until it is fixed.

That sounds like you updated your FoundryVTT version, but did NOT update your Game System version.

FoundryVTT 0.8.6 has a very explicit, 0.8.6-only version you need to update to: The Forge