Well I mixed up a barrel and found a black dot in there... I thought it might be diet or something from my room but then thought it could be something from the vial. I discarded it and redrawed another one and pinned that. Now i am thinking it might have been a tiny piece of rubber stopper? I have never had this problem before, but then I have drawn with only 23G needles. The 21g needle I used to draw it with is pretty huge so perhaps ive cut a bit of stopper which has sucked into the syringe? Makes sense? Just wanted some others thoughts as its pretty scary stuff and now im on trt I'm really looking into my long term safety a whole lot more now.