While in 3rd person play mode, the camera switches to first person in a specific area and some places have invisible barriers on them

I’m very new to UE4 so sorry if this is a stupid thing that i’m missing, but I just built a new area for a map iv’e been working on. When I fly around in the map it works fine, I can place stuff and look around easily. But when I try and go into play mode, the game switches to a strange 1st person mode and there are invisible barriers everywhere, but when I go into a different area that I built a little while ago everything works fine and as it should. I have a video if this doesn’t make to much sense.

I can really use some help so thanks in advance to anyone who helps!

Thanks for the answer but when I turn on the setting to see collisions i’m pretty sure it says that everything is fine in that regard.