Sure thing.
If you got heroes that are preferenced for Attack, and attack phases are proportionately smaller to Defence rounds, then Attack focused heroes have their winrates off by a large fraction. As detailed by the devs that their winrate is based on
(Pickrate x TimePlayedInMatch) / TotalDurationOfMatch
So if that TimePlayedInMatch is shorter, then their winrate is artificially lower.
Because that’s how math works.