Rusted Sword: Rusty Bug

[PutridMeat]

Hoping to save some folks a little time as I was struggling for a little bit trying to 100% the game due to a glitch with the weapon collection 'cheevo.

I first picked up the Rusty Sword from the Yosei Forest IIRC, leveled it to Dark Greatsword, and threw it into the junk pile with the rest of the other useless weapons. Fast forward and I just finished grinding out a few more rare drops and get my achievement - SIKE - no I didn't! I went through my weapon list a dozen times and couldn't figure it out.

Until I realized that, at some point, I somehow got another Rusty Sword. I am guessing from a Mummy, but who knows? Didn't think it was possible to get duplicate weapons. So yeah, I leveled the Rusty Sword... Again... And voila. 100%.