I recently built a new machine with a Asus ROG STRIX B650E-F GAMING WIFI motherboard, everything has been ok so far except the line-in audio volume is changing on it's own. I have my laptop plugged into it and whenever the volume gets loud, it boosts the audio level by about 80% all of a sudden, then jumps back down to the original volume level. I tried reinstalling the audio driver, disabling communication detection, neither did anything.
May I know how your laptop is connected to the motherboard?
Have you tried using other audio input devices or cross-testing different ports and cables?
We also recommend checking the audio driver version or BIOS version and referring to Fix sound or audio problems in Windows for further confirmation.