Can't Login via 1Password 8 on iPhone after 1Password Maintenance on 2023-04-27

Upon further testing, I have discovered that when both 1Password 8 and 1Password 7 are installed on the same iPhone, I am only able to login to my accounts using one of the apps.

Previously, I was able to login to 1Password 7 but not 1Password 8. (I had both working fine, but then I tried to access 1Password 8 during the recent 1Password database maintenance, and got logged out of 1Password 8.) I tried deleting 1Password 8 and re-installing it, but it still didn't work. After entering the e-mail address, Secret Key, and Account Password, I was prompted to select either Security Key or Authentication Code for MFA. If I selected Security Key, the prompt immediately disappeared without triggering iOS to display the Security Key prompt.

I then tried deleting both 1P 8 and 1P 7 from my iPhone. I then installed 1Password 8 first and was able to login to both my Business and Family accounts without any problems using my hardware Security Key for MFA. However, when I then tried to login to 1Password 7 on the same iPhone, after entering the e-mail address, Secret Key, and Account Password, I am prompted to select either Security Key or Authentication Code for MFA. When I select Security Key, 1Password then displays a text field for me to input the six digit Authentication Code.

So it appears there is some bug where if 1Password 7 and 1Password 8 are both installed on the same device, hardware Security Keys will only work with the first app where the user logs in to 1Password, and the other app will then fail and fall back to MFA via Authentication Code.