Formatting dates in table varies

I’ve the folowing issue:
If I bind a table to a tag that’s defined as a dataset and it’s source is a DB using a storedProcedure called “geefFeestdagen()” (returns all entered holidays), and I want to set the date formatting, it doesn’t work!
If I make a copy of the table and directly couple it to the database using the same query, the date formatting works!
See the image below.

Because of the system load with 20 clients all retrieveing this data, I prefer to acquire the data once via a tag and show the data multiple times by letting the table reference to the tag…