pfSense

https://github.com/pfsense/pfsense/blob/a7086b04cae21ca742fdeefd1019ee1401b6dded/src/etc/skel/dot.tcshrc#L71 causes username and/or password for the proxy to be printed if it contains a ?

For example, set your proxy password to "bar?" and then sign in via SSH:

pfSense - Netgate Device ID: 6f04db72ec87aa2218b2

*** Welcome to pfSense 2.4.4-RELEASE-p3 (amd64) on pfsense ***

...

 0) Logout (SSH only)                  9) pfTop
 1) Assign Interfaces                 10) Filter Logs
 2) Set interface(s) IP address       11) Restart webConfigurator
 3) Reset webConfigurator password    12) PHP shell + pfSense tools
 4) Reset to factory defaults         13) Update from console
 5) Reboot system                     14) Disable Secure Shell (sshd)
 6) Halt system                       15) Restore recent configuration
 7) Ping host                         16) Restart PHP-FPM
 8) Shell

Enter an option: 8

bar?: No match.
[2.4.4-RELEASE][admin@...]/root: 

Quoting the variables like below makes the "bar?: No match" go away but I don't know enough about [t]csh to say if it's the correct fix:

if ( "${http_proxy_auth_user}" != "" && "${http_proxy_auth_pass}" != "" ) then