Hi @AaronMark ,
I would suggest you to go through the below Post :
In accordance with that, we would require to know whether there are different formats of date present in the data.
Once we identify the format/formats of date values we can use the solutions provided in the post to convert to DateTime.
Try to Debug the workflow and Check the value of Data_Completamento_Ordine
when it errors out in the Debug Panel.
We should be able to understand the cause better in that way.