Output flow variables inside a loop not iterating

I have 2 nodes (datetime to string, and string to datetime) I want the 2nd node only to act on the columns acted on in the first. This is running inside a variable loop so that I can act on several tables.

To achieve this I’m writing the included_names to a variable:

And then using that variable in the 2nd node:

This works great, but only on the first iteration of the loop. On subsequent loops I can see that the array variable isn’t being changed.

What am I doing wrong?

Hello @rosspyres,

how do you control which columns are converted in the first node? And also what are you really doing here? From Date&Time to String and back? Maybe there is a different way to deal with it?

Described behavior can be due to Enforce exclusion/inclusion configuration in second node. If you have Enforce exclusion option and empty column list you’ll always get all columns converted regardless of flow variable. I found this topic where I (maybe) explained it a bit more with couple of other ideas/remarks: