I just ran a UBRS with HoJ and Recount active.
18 procs from 921 melee attacks
This is a ~2% proc rate so it seems to be correct (need more data to really confirm)
The damage however seems to come from my offhand.
I am using Core Hound Tooth + Distracting Dagger as weapons.
Here is a recount screenshot:
https://ibb.co/ZX28TZT