Error in Flow using date to string transform function

[Bidduam]

I have created a flow, there are two variables that are Date fields (not date/time fields).

I have added those date variables to a add a comment flow and used the transform function on the variables to convert the date to a string. However I keep getting this error no matter what I try.

Error in executing transformer date_to_string

Error Message : Custom date format cannot be blank

Input value :

Parameters : {date_format=NULL_OVERRIDE, custom_format=dd/MM/yyyy}

The date format we use looks like this - 22/11/2023 (dd/MM/yyyy)

The error in the flow looks like this:

The way the transform function is currently setup is:

Both fields are setup the same way.

I can see nowhere that I can set the input date if that is needed?

Help please

[Sonam_Tiwari]

Can you try to add a log action before passing in comments to see what values for date variables are coming from the 1st activity which are then being transformed in comments.

[Bidduam]

@Sonam_Tiwari 

I added the following to the Flow:

It has been added immediately after the date fields have been updated and immediately before the dates are trying to be converted to a string and updated in a comment.

This is what has shown in the log:

[Sonam_Tiwari]

Its empty before its being passed as input to, and being transformed in comments update which I believe is the reason is giving this error mentioned above. If it has been added immediately after the date fields have been updated then ideally we should be seeing those updated dates in the log. 1st thing is to fix why its empty than to check why there is error in conversion of dates to string.

[Bidduam]

@Sonam_Tiwari ok thanks, but how do I make it so it is not empty?

The fields have a value in them, they are updated manually in a sc_task, then saved.

I have no idea why they are 'empty' and therefore no idea how to make them not empty.