CANT WALL IN MY MAP (BUG REPORTING)

I’m working on a TYCOON game, and when testing it on my private islands, I’m encountering some bugs that I don’t understand. I’m conducting all these tests with my partner. The main bug is that I want to move around my team’s house, but it seems like I can’t walk, and invisible obstacles block me when my partner doesn’t experience this issue. And if I perform these tests in a session on the UEFN, these issues don’t occur. They only happen on the private islands. Additionally, for example, some crystals are initially blue, and then on the island, some of them turn black for no apparent reason.