Uniqueness Constraint Migration with Mendix 7.3 issue on null values

In our system we used validation for uniquness on null (empty) values. This works before the migration to "Uniqueness validation" on database. It was exception this dataset: 1 3 5 empty empty   With the database validation this is not possible. In the release notes of Mendix 6.8 it was even fixed to allow empty values. Is this a bug in Mendix 7.3 or is there a workaround to avoid this without writing my own Microflow check.
1 answers

From the releasenotes of 6.8 I gather that skipping the empty values is the intended behavior.
In that case there is no way to enfore uniqueness on that using database validation.

Perhaps a work around might be to have a default value of 0 and add an aditional required validation on the attribute?
Otherwise, I think you're stuck with writing your own validation flow.