Why? Your shell is run under your user (vrogers). You use $ZF(-1) to spawn a child process which inherits everything from parent. Ergo, $ZF(-1) started from shell is also run under your OS user.

Correct.

Terminal sessions are run under OS user who runs the terminal.

CSP and Interoperability jobs run under cacheusr or irisusr by default or some other custom user if you specified that during installation.