Error due to null value for an attribute in "XXXXX" rule

We are encountering the error:

“Error due to null value for an attribute in ‘XXXXX’ rule” while submitting the expense report for approval for P-Card transactions.

As part of our analysis:

• We attempted to disable the concerned rule; however, the same error persists and appears to be syncing to the next rule defined after the ‘XXXX’ rule.
• We tested by creating a cash expense using the same parameters as the P-Card transaction, with only a change in the template. In this case, the approval was successfully submitted and routed to a different rule.
• The DEA and person record are active, and the worker type is set as Employee.