I'm facing a weird issue in our customer org. We try to update some lead objects in our managed package after some processing. We are seeing that sometimes the objects are updated successfully whereas other times we are getting the below Error while updating the objects
ERROR : FIELD_CUSTOM_VALIDATION_EXCEPTION: Attempt to de-reference a null object ERROR : Fields that affected this error: ()
We are not able to pin point which field is causing this issue since it does not show which field causes the problem and there are other apps on their org as well which are updating the lead object.
Also when new leads get created, the previous ones that were failing now start getting successfully updated. Not sure how to find the field that is causing the issue or how to debug this further, any thoughts?