hit the accelerate pedal harder

LOL while starting up? This isn't a carburetor engine. lol

When you filled up with gas, did you "top off" the tank? (After pump stopped, you squeezed more into it to top off).

Yeah, on modern drive by wire cars, the ECM controls throttle and fuel delivery at startup. If you put your foot to the floor it may cut fuel delivery for a "clear flood" mode.

In answer to your original post, there's an ECM update that's supposed to fix the issue (and the idle dip issue). It happened to me twice in the past year, none since I reflashed, though it's so uncommon I can't really tell if it's fixed.

I have had it happen a handful of times. No worries.

Crappy/low octane gas possibility?

its normal, happened to me a few times...

10 series also

My FRS is in the shop now and among other things they are replacing the ECM to an updated one. My idle "misses" several times before smoothing out at cold start up mostly. I have never had the rpm dip down or throw a cel. Should have it back tomorrow :-). Really hoping this fixes it. Will report back ...

Nothing a tune can't fix.

I have heard this as well, that the OFT stage 1 fixes many of the "poor factory flash" issues. Looks like I will have an updated ecm as a baseline for tuning though.:-)