Question about 18650 3.6v vs 3.7v nominal voltage.

So I just bought my first fpv radio transmitter, the radiomaster boxer, and in multiple places, in the manual and on a note in the battery compartment it says specifically to use 3.7v 18650, not 3.6v. It actually says not 3.6v, but every reputable 18650 I can find says it's nominal voltage is 3.6v. I can also use a 7.4v 2s lipo pack according to the manual. Just wondering if maybe this warning about not using 3.6v 18650 is maybe bs and it should be fine, I just don't understand how not a single 18650 from any of the recommended retailers would fits this requirement.