Invisible invincible enemies and falling through the map

Platform: Ps4

Description: I had 3 damaged dogs that were invisible to my friend but not to me, they were able to damage me but not him and I wasn’t able to kill them. There was severe frame drop and spawning of enemies at random points while we were at the location (Norrmyra Artillery Base). I also fell through the map at multiple points (just outside the East - South-east entrance to the base) and even fast traveling to another area couldn’t get me out of falling through the ground.

Steps To Reproduce: I haven’t been able to reproduce it and have no idea how to honestly.

Images / Videos: Twitch.tv Clip
This happened during my stream and the first time I came in contact with the invincible enemy was around 24 minutes into the video and from there on is all buggy. (Sorry for the screaming and loud audio it was a lot happening at once, but I hope you at least find it entertaining lol).

Host or Client: I was in a co-op session with my friend and he was hosting.

Players in your game: Just the 2 of us

Specifications: Ps4 slim

Platform: Ps4 Pro host, Ps4 slim client

Description: invisible runners for the host. Client could se them and had too fight them. Host didn’t take any damage even when the client died next to him. Industrial area north of Östervik. Will provide more accurate cordinats next time I start the game.

Players: Host and one client