I’m having vertually the same issue’s. In addition my co-op partners cannot see my basses when i’m hosting as I cannot see their bassed when they are hosting. This applies regardless weather there are 2, 3 or 4 players in the co-op, no one can see any basses, they all show up a neutral’s.
Kinda defeats the point of building basses for all of us. Base defence or attacks were a main stay for our group (9 partners) just a month ago then poof…gone.