Taz’Dingo’s level 20 description says that it heals for 50% of damage dealt during the duration of the unkillable.
Even while Zul’Jin is blind he still receives the healing.
I suggest either update the current flavor for his level 20 to say he is immune to blinds (and allow him to do damge) or correct it so that he doesn’t gain heals from auto attacking during the duration of the blinds.
Are you sure Zul’jin did only AA’s in your case? From what I know, “missed” hits from blind do not give him healing from his 20. That said, he heals 50% of all damage he deals, including his abiliies like Twin Cleave though.
As the description states:
Increase Taz’dingo’s duration by 1 second. Upon expiring, Zul’jin heals for 50% of the damage he dealt during Taz’dingo.
So it’s not limited to his AA’s.
his 20 says he will heal for 50% of damage dealt, his Q and W will do damage even while blinded and contribute to the effects of this talent