"Omicrons (B.1.1.529) most recent common ancestor is AV.1. Relative to this MRCA, Omicron has 25 nonsynonymous and 1 synonymous mutation in Spike, and 13 nonsynonymous and 6 synonymous mutations in the entire rest of the genome."

This seems improbable, but AFAICT you wouldn't expect it even in lab passaging.