It’s not another TFA plugin. It’s a plugin that allows users to login using their mobile numbers and OTP sent through SMS to their mobile numbers. It has no reasons to be present on the admin login page. I have written to the plugin author who is working on it to remove it from the admin page. The plugin is called Digits available in codecanyon.
Yes it was the culprit. Disabling it allows me to use the TFA plugin as usual. Thanks for the heads up. I should have suspected it earlier though.