@Anonymous
Usually flow errors out when the required field is either not configured properly or there is no data being passed onto the required field when inserting the data into picture library using power automate.
It can be either one of the two reasons why your users are facing issue when updating information into picture library when a field is being marked as mandatory. I suggest you to please check if the user is populating the data in the required field or not.
If the users are populating data in the required field and are still getting error, please share error message so that I can assist more on that.
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