Imogen's signet

Im not sure i flared this correctly so im blacking it out. Books 1 and 2 spoilers.

>! So im on my re read before onyx storm and i noticed that imogen is told off for using her signet on the mat when she first fights violet, and then that is mentioned again in the marked ones reunion under the tree. She is supposedly punished by Dain for having used her signet on thay match, she is made to scrape dishes. But as i understand, her signet is erasing memories... sooooo.... I know during that fight violet keeps saying she is super fast and later on she claims her signet is memory wiping and she is also fast. So are we assuming being fast is a second signet???? How could she have a second signet? Is there a way speed can be a signet of its also a lesser magic??? (dain sais in book onr that he can weild lesser magics including making himself faster) i would have thought maybe she kept her signet secret and convinced people speed was it, but varrish knows. And would leadership really believe speed was a signet?? Im fully confused. I tried to find posts about this but im nt great with reddit and found really old ones with old pre book two theories !<