I've had the same issue a couple times myself, again just now. I've looked in the community section and see this is a very common issue since at least 2017. It doesn't seem like Adobe wants to fix this, just have users accidentally keep using their credits. When I'm viewing a photo in a Library as the larger preview, I click over to another image thumbnail to view it, however as I click on it the License button appears where it hidden before, and in a single click meaning to open that thumbnail larger, I've been tricked into licensing the image. What a horrible user experience! I contacted help for them to tell me the images are non refundable per their policy but as a courtosy gesture they'll add a credit to my account. Oh how nice, your bad interface tricks people into licensing non refundable images! There's many other stock photo outlets, some of them free, just so you know you're not the only game in town Adobe Stock.