Worried that PayPal popup is a fake

[themightyacorn]

I tried to pay today for an item today and instead of being able to sign into PayPal to pay, instead a suspicious looking popup appeared on top of my ebay page asking for all my PayPal details. I didn't give my details because it looked dodgy, and I read that there have been previous popup scams.

Are these popups genuine? Has the payment method changed in the last few days? I'm on mobile, using Chrome as my browser.

Thanks.

Edit: as I can't seem to leave a reply.

I ran a malware scan. It found nothing. I can't seem to block popups on Chrome mobile, or at least not that I know.

Why did every time I clicked on "pay by PayPal" this popup appeared and it wasn't possible to click through to the PayPal site as usual? How do I pay without triggering the popup? Can I go straight to PayPal and do it there?

I already sent a message to the seller apologising for the delay.