Quite a few old and recent threads on this
Sampling externally or internally it’s the same, this is in the manual …
GAIN allows you to amplify or attenuate each individual sample without affecting any track parameters or locks. On recorder buffers this setting defaults to +12 dB to compensate for the attenuation the headroom of the audio engine inflicts
It’d be good to get a more detailed heads-up as to why it is like this !