Question ASRock H670 PG Riptide 4 beeps on start

[ROODAY]

Does anyone know what this means? I tried checking the manual but there isn't anything I could find that specified beep codes. Googling this said something about system timer, but what I don't get is on the very first boot I didn't hear these beeps (freshly installed motherboard/CPU/RAM, reused old components for GPU, HDD, PSU etc.). However on subsequent boots (and still continues now) I hear 4 short beeps. There doesn't seem to be any issue with the hardware itself, as the system is running fine (Ubuntu server). Could someone help me diagnose this?