It is your problem if you are attributing it to her being able to avoid the kaguya arm.... How old are you....
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^^ This is for you, see here this is right after Tsunade uses her seal to fight orochimaru, it reforms and yet she loses her young state because the seal might be visible but it was in fact near empty. Goodbye.
It's doing the same thing Tsunade's did against Madara when it was running out.
If you look on the bottom panels of the last scan, you see it does it again and she thought she failed as getting sasuke out of there as she is about to collapse this time from absolutely using it.
Eitherway none of you can say that this does not prove my initial claim that Sakura that was avoiding kaguya's arm was low on chakra.