eBay is having a *lot* of glitches at present
I have just got off the phone with their stores support because of "bugs" in the relisting forms that add payment methods that I do not accept and remove PayPal button
they told me there are many problems occurring because eBay is getting ready to roll out a new look and so the old format is "buggy"
sheesh one woulda thought they had enough experience by now to do this smoothly huh
it is very possible that the missing button for you was another of the glitches mrsD