ssh GSSAPI authentication issue

[Joe Sapp]

I'm trying to run some remote jobs with parallel (20170322) via ssh,
but the authentication system here for ssh is set up to use GSSAPI.  I
have to ssh into a Linux machine, then from there I run parallel.
>From what I understand of the authentication system, my credentials
are forwarded over the initial ssh connection, allowing me to ssh to
other servers on the network.  There seems to be an issue related to
this for how parallel determines the load on the remote server; I have
no problems when using public-key authentication.

For example, this works, with the command being run remotely and locally:
  seq 10 | env_parallel --sshlogin :,4/$SERVER echo

These do not:
  seq 10 | env_parallel --sshlogin :,4/$SERVER --load 75% echo
  seq 10 | env_parallel --sshlogin :,$SERVER --load 75% echo
  seq 10 | env_parallel --sshlogin :,$SERVER echo

by which I mean that I am prompted for an alternate credential.  It
seems to me that parallel is not passing the credentials on when it
requests information from the server.  Can anybody provide some
guidance or suggestions for debugging?

-- 
Thanks,
Joe