yeah basically it doesn't need to "inject" or be "internal" to be detected, if an external, calls an engine function in the code, it will be detected. (such as bone position, visibility checks) this is why they say your externals are 99% undetected, because SOME externals are lazy and/or shady and call (game) engine functions that make it technically internal
EDIT:
the external that got me banned, I searched for days and days, and it was for 1.1.177 (so I had to update the offsets), and it was in German, so that should give you a clue as to how rare a detected external is.