Yes, I tested positive for fentanyl like 3 times due to taking pressed "xanax" bars from the same source. I never OD'd but had a few immediate blackouts from small amounts. It was almost like the retards making them were using proper scales to weigh the fent and cheap ass ones to weigh whatever RC benzos they were using. My first blackout lasted 10 hours from 1.75 bars then a week later the same 1.75 bars caused an 18 hour blackout followed by 48 hours of memory lapses.
To this day I still wonder which benzo caused that 2nd incident, as I had meth in my system but it's effects were just completely obliterated within minutes