Aeroad CF SLX Frame Weight Difference?

Was comparing the Aeroad CF SLX 8 AXS SPEED to the same bike in DI2 spec.
I'm aware components are different, and will therefore have different wheights. I was surprised to see that Canyon specifies the frames at different wheights: 1173g for the AXS version without SRAM parts, vs 1050g for the same frame without Shimano parts.

Who can explain the difference to me?