You cannot type function names or their datapack name in /function ín uppercase without getting an unexpected error. If you do

/function kitPVP
// this will happen:
Expected whitespace to end one argument, but found trailing data at position 12: ...nction kit<--[HERE]
// if you do
/function kitpvp:INIT
// it will still throw an error, as INIT is uppercase

How to reproduce
Write /function
As the first argument, write anything in any uppercase letter, for example /function kitPVP
Watch the error

What I expected to happen
..was that functions inside the /kitPVP datapack would run. Or, that I will get an error telling me to write in lowercase, at least