Characters drop through terrain above ~12,600-12,700m

I have a third person level that also includes a dynamic pawn. If I switch from the third person character to the dynamic pawn (unpossess/possess) the third person character falls through the terrain if the dynamic pawn is above about 12,600-12,700m. My level BP disables physics on the third person character when it is unpossessed. Do I need to have a sublevel for high altitudes?