I'd still like to know what is messed up, though.

As the normal user for which pulseaudio --version doesn't work, can you try
spawning sudo dtruss -f sudo -u $USER
/Applications/x2goclient.app/Contents/exe/pulseaudio --version

Yeah, I know this looks weird since we need to use sudo twice, but dtruss is
only working with elevated privileges, but since root is able to execute PA
--version just fine, we need to switch back to your other user account...