Najib Ahmadi wrote:
. . . Before when I add the fillet it normally adds the fillet both inside and outside automatically. . . .
I've never seen it do that. We are talking fillet feature here, not sketch arcs, right? Maybe when you pick a few faces the fillets will propagate to an inside corner, but not by just picking an outside edge. Or are you taking about a shell feature, where you get an inside fillet but only when the outside fillet is larger than the wall thickness? I guess I need more context to answer.
And don't forget: First add the fillet on the outer edge, afterwards use the shell feature! The right sequence is key!