Don’t know anything about Particle Photon’s and I haven’t checked your sketch but I do know the Blynk guys have coded virtual pins different to digital pins. Locked up my Arduino with ESP regularly. I had to ditch all the virtual pins and use digital pins which is a real waste of resources.
Just this evening I had to code around the virtual pins I had tied to a couple of timer widgets.
More details highlighting the ‘issue’ are at Blynk Libraries