Here's a fun one!
On my Linux machine KSPProfiler fails to load because it doesn't have access to KsmUI information when it loads
My guess is that this problem only appears on Linux because GameData folders are loaded in alphabetical order, and on a case-insensitive filesystem 'Ksm' comes before 'KSP' but on a case-sensitive filesystem (such as ones used on linux), 'KSP' comes before 'Ksm' (since the uppercase letters are before lowercase letters). I don't know if this is actually the case, but renaming the 'KsmUI' folder to 'KSMUI' makes the problem go away so it's my best guess.
The real question is why are plugins loaded alphabetically without some kind of dependency system anyway.