Got a character sheet with numeric inputs. So they render with the convenient up and down little arrow buttons, that the players tend to use (rather than clicking to enter the field, then typing, then tabbing out / clicking elsewhere to make sure that the update of the value has been taken into account). The problem is (or seems to be) that when a player quickly click the arrows, and then immediately click a button (type "roll") that triggers a roll using the supposedly updated value(s), sometimes the update seem to be ignored by Roll20 (or been taken in account later/too late) : the player's sheet occurance is visually up to date but not the attribute behind, at least on the server/the GM (me) looking at the same player's sheet. FWIW, the roll is calling an API function. I can't reproduce it when testing on my own. I'm under the impression that if the player clicks elsewhere/put the focus in another entry filed after clicking the arrow, the change of focus really triggers the update and the roll is fine (using the updated attribute(s)). But if the focus was the input's arrow and then immediately the button, the update of the attribute isn't triggered (sometimes ?).
