Now, this is just my personal experience, so take it with a grain of salt, and maybe someone else can confirm one way or the other, but when I got Protect The Runner, I was playing with a group, and we stated out in Gambit Prime. We had a few games where our runner had 75+ motes banked, with zero dropped, but it didn't pop, so we switched to regular Gambit, and got it on our first try. The only thing we could think of was that the Gambit Prime blockers draining some motes from our bank counted against the runner's banked total, despite what showed in the final total. Since bank draining is now a thing in the unified Gambit mode, it may be the case that you have to meet the requirements, while also keeping any motes from being drained from your bank.