It seems Supermetrics MATCHES REGEX filter wraps the regex term in the .* (wildcard & 0+quantifier). This means that a filter like Campaign MATCHES REGEX alwayson will return results for "campaignX_alwayson".
DataSlayer does not do any wrapping. This means that migration does not work for queries that use the above pattern.
Could the following please be added.
if MATCHES REGEX is used and there are no explicit .* wrapping the value THEN wrap the value.
This is the expected behaviour and there are no obvious edge where it would break the expected behaviour.