What Blynk library version are you using? There was a issue with notifications and an older library version a while ago… EDIT - nope… it was the App version, not the Library 
Strangely the only other RPi based notification issue I could find here was also with WiringPi, and no clarification if App upgrade helped or not… Perhaps notifications don’t work with WiringPi? @vshymanskyy is this a question for you?