Today, my 30 days finally expired on my login using my 2FA key. When I was initially setting up my 2FA authentication, my phone could not scan the QR code on my screen to add it (I am using Authy over Google Authenticator). This was strange, seeing as it worked here on the XF Forums, but I disregarded it as a camera issue or something silly, and manually entered the key.
Now, the issue I came across today was that when I was prompted to enter my key, the code I was entering directly from my phone using the exact same profile that I had done when I first set it up, would not provide the right code, or at least the forums consistently rejected my code from Authy. This was frustrating, and I had to use one of my backup codes in the meanwhile to restore access to my account.
This seems like a major issue and I have no idea if it's an issue with the authentication service, XenForo, or my installation. This is something concerning to me and all others who use 2FA on my site because it seems like users could potentially lose access to their accounts.