This just happened on some sellers, somes did not.
I did chose paypal, but when I ticked the gift card amount, every payment options went black like this, I cannot choose any of them again, and it said "
The entire order amount is covered by a coupon, gift card, or eBay Bucks." on each option.
If I untick the gift card, it will be normal.
Additional information: I found out that on the listing that seller do not offer the "Paypal Credit" option (You cannot choose this option when check out), this thing does not happen.
Picture below.