I am waiting on new screws from Flow after having the same thing happen. I am chalking it up to the use of bottom end screws as even with the right driver the metal used is way too soft.
A #3 philips screwdriver would not have stripped it like that. The pic shows you clearly used something else. Arguing is pointless. Drill it out and put in a new screw. Problem solved.
Like I said I had a similar experience before with another set of 390bosses, so I was extra careful with my brand new set. I did use #3 screwdriver. Way to still recommend drilling the screw out when I clearly stated I didn't want to and was looking for other
I will however try an extractor first and then an impact driver. Thanks for those advice.