Bitcoin Core – Why is my P2P_V2 peer connected over a v1 connection?

Bitcoin Core 27.0, which natively supports v2 transfers (BIP324), was released a few days ago. I’m already seeing a few colleagues using the /Satoshi:27.0.0/ user agent and all of them have the P2P_V2 service flag set. However, one of the peers (inbound) connects over a v1 connection. Is this evidence of network tampering (failed v2 connection being retried as v1), or could there be another reason?