I'll try resetting and logging in from a clean device to see if it helps. I also think maybe something on my phone triggered itIt could be caused by device security issues or hidden malware. Try a full factory reset, reinstall Facebook, and change your password from a verified device or desktop browser.
There are many tips that can help you change information right on the strange device but it will be difficult to share hereWhen I first received the device, it often had strange errors. I couldn't change the FB password and 2FA code. Is there any way?