I am executing a script to keep fields synchronized between Epics and their children. When I run the script it updates the children with a PUT
def result = put('/rest/api/2/issue/' + issueKey)
Custom Field 12802 is updated perfectly fine, but Custom Field 10202 is not updated and just remains the same. There is no error thrown and it is supposedly executed successfully. I've triple checked that the custom field ID is right and the 3 sub-fields all exist and are populated. Even stranger, this field is also updated on Subtasks, and that works fine as well with the same format, though without the first CF (12802)
Might be pointing out something obvious here but have you checked whether the customfield 10202 is on the create/edit view of the issue where it isn't working?
The fact that it does work for subtasks and not on the parent made me think in this direction.
Let me know if this helped!