Including attachment in the Auto Creation does not work

I have a setup to auto create records based on a BP line items. I have set up the setting as below picture. the records are created and all fields auto populated correctly. but line item attachments are not copied into the created BP. Both BPs are Line-Item type.

I tested the feature in Meeting and it copies the attachments from line item to destination record (Action Items) the difference is Action Items is a Simple type BP.

I tested my problem in 19.12.11 and 20.12.5 environments.