Hi steph_giles i don't think you understand what @splarson24 is saying, i have the same problem. I tried to login today on Amazon, i have the One-Time code feature turned on and the codes are generated within 1Password. When i tried to login today when i got to the step where it automatically fills the code i get an error saying that the code is incorrect. I managed to get into the account by using a different two factor method and i removed and re-added the 1Password One-Time code feature by scanning again the QR code with the 1Password Browser Extension and it still says wrong code even if it scans the code without a problem and adds it to the Amazon entry.
After i found this post i tried to see if the 1Password app on my phone is giving a different code to the same entry in the same time compared to the 1Password extension and it actually gives a different code which guess what, it worked. As i am writing this message i have in front of my eyes the same Amazon 1Password entry both on my phone an in the Browser extension and it shows 2 different codes, for the same entry, in the same time, so it's clearly something wrong with it...
I checked the 1Password Desktop app also and it shows the same code as the Browser extension, which doesn't work. The phone app though is showing a different code for the same entry which works, keep in mind that i don't have multiple OTP set-up for the Amazon entry and the entry and OTP was set-up via the Browser extension and i removed it and re-added it from Amazon and 1Password a couple of times to test it, same thing...