I migrated a character, but it is different in the target project

Hello, I downloaded a project with a character that has a combat system (melee/ranged/weapon switching) and migrated it into my current project. However, when I load the character in my project, I cannot switch weapons as I could in the downloaded projected. Im thinking this is possibly due to the start script not expecting a change in pawn? Im really not too sure, any help would be very much appreciated, thanks! By the way all blueprints and content were successfully migrated, it seems to be an error in the combination of the two projects.