Truecaller reads new SMS sometimes even without having SMS permission I use Redmi 9 Prime. On that I use Truecaller app. I want to use Truecaller only for calls and strictly not for SMS. So I never give SMS read permission to Treucaller app.

But still sometimes Treucaller read new personal SMS. Till now did not see any service or OTP SMS in Truecaller. Dont know how come.
What can be the reason or source of getting this possible? How can I stop Truecaller strictly touching my SMS?
During app installation from play store, you may have given permission. Without it app will not install. Uninstall and reinstall truecaller.
Which app is default SMS app.
Open app / clear cache and storage. Force stop the app. Restart mobile. Again check permission status.
Last option start mobile in recovery mode and clear cache partition.