im assuming its because shes been treating everything as normal skinship between girls. when she got turned into a guy, it made her overly concious (because she was thinking "im a guy" during it) and she realized that whoa all that contact is actually really suggestive. it made her acknowledge the proverbial forest so to speak.
I already made that point, but everyone prefer to keep bitching about it.
"I made my point, therefore anything else is just bitching!"
Kobayashi having an 180° in personality is just dumb writing even if it's for the lulz, without a dick, she is constantly tired due to being overworked and has nothing resembling ANY sexual drive in any way without any supplement, the love potion is easily dispelled for a joke anyway, so what was the point even.