cr:6.6.5d

If the trigger condition is proceeded by an ordinal as part of the condition, the effect will only trigger on the specified ordinal time(s) the condition is met, relative to the specified duration. If the effect becomes functional after the specified ordinal time(s) the condition would be met, the effect will not trigger for the rest of the specified duration.

Example: If a card has the text “The first time you boost each turn, gain an action point,” and it is put into the arena as a permanent after you’ve boosted that turn, it will not trigger the next time you boost that turn because the ordinal time “first” is relative to the turn and has already happened.