Learning Withdrawal Approval not working

We are trying to build a learning approval rule where in case a learner attempts to withdraw from Course where offering is selected AND Offering “Final Withdrawal Date” is in the past, then system should auto reject the request. We have already created a date type DFF at the offering level called “Final Withdrawal Date”.

We are trying to use below approval condition in BPM but its giving us an error, which we believe is due to it not being able to read offering DFF data. Any suggestions/workaround to meet our requirement.

APPPROVAL RULE

(Duration.days between(Task.payload.Offering Specific Details.result.clsAttributeDate1.toGregorianCalendar(),CurrentDate.date) < 0) AND (Learning Item.result.Learning Item Type Code == "ORA_COURSE")