Access to legendary weapons without the required masteries?

First I don’t know if this a bug or error, but according to other players are my masteries much to low.
Since the last big update I posses several legendary weapons within my backpack. So I posses the Bronzelock Pistol, which requires a 40/40 blue/brown msstery. In both I posses, as Level 101, only 17!
And I never purchased anything so far.

What are the steps to make it happen again?
I don’t know, because they appeared after the update

Do you have any screenshots or video you want to share with us so we can see the problem? Attach them to your post!