PP has it's own LUT library. The default input dropdown in Lumetri can be extended by adding LUTs to "...Adobe/Common/LUTs/Technical". The whole list is sorted alphabetically including the custom LUTs. In my case the existing LUTs were pushed down by 4 additonal items.
Now if you select something from Premiere's presets like "Alexa_Default_Log2REC709" and open the project on a pc without the added custom LUTs, it will now show "ARRI_Universal_DCI" with the wrong colors applied. Why? Because the ARRI LUT is 4 entries down from the Alexa LUT and the list is missing the 4 custom LUTs from the top.
This does not happen when selecting a custom LUT from the list. Those apparently are saved in the project file, I think?
Thankfully the list of built-in LUTs is short, but this still leads to frustrating guess work if you notice the wrong LUT. I haven't tested this on creative LUTs in Lumetri though.