Why are session variables only sourced once?

[magikid]

What is the point of having this in the session variables?

# Only source this once.
if [ -n "$__HM_SESS_VARS_SOURCED" ]
  return
end

I run tmux in all my terminals so this $__HM_SESS_VARS_SOURCED gets passed to each new pane which means that if I want to actually update my session variables, I need to exit tmux entirely which is not ideal.

[rycee]

The session variables are related to your login session and it can become quite confused if different parts of your session have different views of the world. You can always explicitly create a new login shell using bash -l.