Celerity + hex-flash = [EXPLOIT]?
When hexflash is used, your movement speed gets a momentary 130-140 point boost, (which is because you need to hit the ground running, else hex-flash is much more cumbersome) and 50% of the time Celerity decides to apply a 1-2 second AP or AD bonus (16% of it in AP or 9.6% of it in AD, 23 AP and 13 AD respectively).
The inconsistent behavior of Celerity is what makes this ambiguously exploitable. Rapid fluctuations in movement speed aren't always recognized, as the Celerity bonus updates less frequently than movement speed does.
Technically, characters like Zoe can "exploit" this in the early game by pulling off hard to land nukes with a hex-flash initiation, but since arguably Celerity and hex-flash are doing what they're supposed to do, it's a fair niche to play with. Any character with a heavy nuke or multiple spells to discharge in under two seconds can use hexflash as a gamble to increase their AP or AD while their attacks/spells land.
I've considered the ethics of writing this thread, but given the ambiguity of the situation, the randomness and small window of opportunity in the effect, and the fact I want to light a fire under the bug team have made this my only recourse. I've written another thread about how Celerity has a bugged interaction with Zoe's ultimate (because it lowers your movement speed to zero for 1 second and sometimes results in Celerity bonus AP loss right around when your nuke lands), and I would be very pleased if Riot deletes this one (indicating that it is an exploit they're keen to suppress and therefore FIX)