Thanks for posting your results. I did suspect that this would be the case.
DDR4 RAM has tables to tell the motherboard how to automatically clock/time the memory. XMP is an extension of that table that specifies configurations outside of what JEDEC (the developer of DDR4) recognizes. You can think of XMP profiles as the memory manufactures’ tested-and-suggested overclocking profiles.
Anything not found in this table and running at 1.2 volts can’t be specified by the normal table as it’s not technically part of the standard. If your DDR4 so-dimm’s advertised timings is not in the table, or it’s not at 1.2 volts, it’s almost certainly using XMP profiles to get there. So be careful to avoid 1.35v modules for this laptop.