Kawasaki Triples Club

Has anybody had an issue with Genuine Suzuki gaskets swelling?
Or am I just unlucky? Bought off Ebay from Suzuki_expert, there's loads of good feedback on his page

What fuel are you using as the higher ethanol in modern fuel can cause issues with carb rubber parts.

Super unleaded
I need to get back in touch with the supplier, he said he's never had an issue with them, maybe they are older stock