Until it suddenly isn't in either of these paths, maybe because its required to run in some quirky setup.

Hrdcoded paths for things a program doesn't bring with itself, should be avoided in general. There is a reason $PATH exists and is easily extended. It is the users/admins responsibility to make sure envvars are set correctly, and it's the programs responsibility to give a useful error message when it cannot locate the programs it expects in $PATH