Isapartof table not pulling order no. Automatically

[DPM_reports]

Hi I created a table with a ref table and also marked isapartof in the source table, yet I am not able to auto fill the Lot No. from the existing row, I was able to do this for another table similar to this, yet I am facing issue here, not able to figure out the reason.

Even though the number is being automatically pulled n showing in the form as in photo below, the same is not reflecting in the Google sheet and hence when I go back to view the data, it shows blank, as the lot no. is blank in the Google sheet