Prior to #15471, we had a warning for 50% of versions being unexpected as a whole. Overt ASICBoost abuses broke that, so it was removed.
This restores the warning, but only looks for 50% of each version bit independently, or 50% with an unknown version schema. Hopefully this shouldn’t get triggered by (or at least can be more practically avoided by) ASICBoost stuff.
Additionally, it changes the phrasing of the warning to reflect the uncertainty of the cause, and avoid searches from turning up “not to worry” responses (that were given to the now-removed warning).