Apple Transporter Asking for app-specific password

I am trying to troubleshoot a difficult problem that only appears on IOS physical devices (not emulators, Chrome, Safari, Android, etc.). I have also been unable to use Safari to debug the phone. The only effective way I’ve found to debug is to compile the app and send it to the app store and use TestFlight. After about 8 uploads today, Transporter suddenly started asking for an app-specific password.

I can generate a password, but I don’t know exactly how to use it. Where do I put this password? I’m using Capacitor. I am out of environmental variables.

I’d also love to know what this suddenly started happening. It changed in-between builds, about an hour window. I didn’t make any change to my account. I don’t want to rant here, but it really feels like Apple is actively working against PWA developers.