This is normal, with newer versions of android (probably 10+) there is a feature that checks and removes unused permissions from apps in the last X days.
Thanks for that link! I was aware of that feature hence why I was curious which cases where apps get additional permissions rather than lose as expected.
According to the OP here, it does seem like a pain in the butt to disable - https://support.google.com/android/thread/268170076/android-...