I have seen this is in the Black Sugar I have grown recently it didn't appear to do much to the whole plant and mostly resided in the branch it showed up on. removal of the leaves helps but it will show again mostly on outer leaves. Did not affect the flowers that I could tell. some sources have pointed to tmv but doesn't act like it and hasn't showed elsewhere in my plants. It probably is a mosaic virus of some kind but seems this one is hopefully benighn. I haven't dived too much into it yet.