Master Pack Transfer Order > Adding to BOL - Error about sites

Can anyone add a transfer order shipment to a masterpack and then link that master pack to a BOL?

I can’t seem to do it in 10.2.500.8- I get an error (seen below). And yes, they all have the same ship from site: the transfer order shipment, the masterpack, and the BOL.

Business Layer Exception

The site on pack 15906 must match the BOL site.

Exception caught in: Epicor.ServiceModel

Error Detail

Correlation ID: 3a974dd4-bf03-496f-8a5c-2dae59cbcbd4
Description: The site on pack 15906 must match the BOL site.
Program: Erp.Services.BO.BOL.dll
Method: linkSlips
Line Number: 2080
Column Number: 41
Table: BOLHead