it must be hard to reproduce, as I haven't fallen through the floor in months
I've been consistently having issues with this on every map - basically my mech/BA/tank/Plane will refuse to clip on buildings at all. In most maps the hangars are built directly onto the terrain with minimal distance, so my mech/BA acts as if it is walking on the terrain floor (I lose about 3ft. of my player/mech into the floor when viewed in spectator), but in maps such as thunder rift (or in the clan hangar on sandblasted), the hangars are built directly into the terrain with the terrain effectively removed underneath it. This means the second I walk over the terrain edge, I fall through the map indefinitely.
I'm connecting from Australia, so there is a chance that this is related to the netcode/sync issues.