It's all about money and licencing to workshops.
Standard SAE OBD trouble codes are free for all, they begin with P, C, B or U. These include a number of manufacturer allocated codes, but these are pretty basic and limited.
See here
https://www.outilsobdfacile.com/data...-code-obd2.php
But each manufacturer has their own "hidden" proprietary codes which are the full detailed set of codes and there are literally thousands on our cars, but only readable via software licenced to read them, i.e. paid for usually,
See if your Carly app codes begin with P, C, B or U? If so its a generic reader.
If they are Hexadecimal codes then they are BMW's own codes.
ISTA reads the full suite of BMW codes, as you expect as it's a BMW system.
Again other workshop diagnostic systems are licenced for this, but they have to pay $$$ for workshop licences if they want full diagnostic capability per-manufacturer.