Sorry to bump this up, but have had this error popping up for a while now, and now I'm nearing a release build, figure it's important to get these errors stamped out. I've tried deleting the PUN folders, PlayMaker PUN, and Array Maker etc. as suggested earlier in the thread, and reinstalled/updated all of the above, but the error still pops up on the host every time a player joins/spawns. The only thing that does seem to remove the error is to remove the Playmaker Photon Proxy script from the Observed Components of that prefab as suggested above, but I'm not sure what other issues this might cause. Is it safe to do this, or is there another recommendation? Thanks!
Edit: Just to update, I've been using it with the observed component removed for the past couple days and from what I can see, all seems to be working just fine. I don't understand exactly what the Photon Proxy script does/handles though, so not sure if it'll come back to haunt me down the line