when querying revoked certificates, you should use 2 queries:
Get-RevokedRequest -Filter "NotAfter -ge $DT","RevokedEffectiveWhen -ge $lastDT","RevokedReason -eq 6" -Property "RawCertificate"
Get-RevokedRequest -Filter "RevokedReason -lt 6","NotAfter -ge $DT","RevokedEffectiveWhen -ge $lastDT","RevokedReason -eq 6" -Property "RawCertificate"
use first query to save revoked certs with "Certificate Hold" reason to a desired folder. The second query dumps all revoked certificates except ones retrieved from previous query and save them to a desired folder.