I have a new theory.
It seems lately that Sanji is trying to actively avoid combat.
Maybe during the skip something did happen in his battle with S-Shark (whether he ripped his arm off or something else) and he scared Nami. If she told him not to do it again, or became afraid, then he could be trying to avoid fights in order for it not to happen again until they have more time to figure it out.
Or if he scared her, maybe Vegapunk saw it, recognized it and told him to avoid fights for the time being until it can be looked into.
If this is a thing, we might get a flashback to the fight if he's forced into combat/can't avoid it anymore.
This would explain why he hasn't come to the defense of women last chapters, and ties into Oda saying to watch him in the future.