At the start of a new session — Globex open at 18:00 ET or RTH open at 09:30 ET — the volume profile is empty. The first trades that print immediately become the VPOC by default. The first 50 contracts at one price beats the zero contracts at every other price.
As volume builds, the VPOC can shift rapidly. Two or three migrations in the first ten minutes is normal. The session is finding its initial value area, and until enough volume accumulates somewhere to establish a stable VPOC, fair value is genuinely contested at multiple levels.
This is why VPOC Migration Pro has a Mute at Open setting. Voice alerts during the first chaotic minutes are mostly noise — useful as information, but not as audio interruption every 30 seconds.