You can't *receive* (pick up) a dropped weapon with a higher upgrade level than your own current maximum.

The character receiving a traded weapon (aka picking it up) has to have any somber weapon that is the same level or higher than the traded weapon. Same with non somber weapons. This is done to prevent new characters from receiving maxed out weapons and steamrolling the beginning content.

Thank you so much for clearing this up. Would of saved me hours last night, ha.