Hi,
Did you try to copy the GUID of the old on-premise group in the attribut ms-ds-consistency-guid of new on-premise group ?
You can also convert immutable ID of the azure group using the powershell command below and copy it in MS-DS-Consistency-Guid
$ms-DS-Consistency-GUID
= [GUID]([system.convert]::FromBase64String($base64))
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