Hello,
1/ When the product has default variation selected it shows “add to cart” https://prnt.sc/kOGZaVpvAZLH https://prnt.sc/GIxe6wgN5nz_ , in other case variable product shows “Select options” – https://prnt.sc/QPInCnu_tREg , when the product is out of stock it shows “Read more”, so there is no bug.
2/ I do not see the problem on your site right now. Was it solved?
Regards
