GitHub SSH hang's up after ~6 min

[freedom-foundation]

GitHub SSH hang's up after ~6 min.

1611_King_James_Bible $ git push Enter passphrase for key :
Enumerating objects: 1510, done.
Counting objects: 100% (1510/1510), done.
Delta compression using up to 8 threads
send-pack: unexpected disconnect while reading sideband packet
Connection to github.com closed by remote host.
Compressing objects: 46% (702/1507)

possible solutions: stage compression before calling GitHub SSH, disable compression- not sure what is being compressed here: core compression 0 show's no change, git add/push ~500 per push.

Q. What is the "Delta compression" which happens when using git push?

[freedom-foundation]

trying to undo the commit of a failing push using
$ git reset --hard HEAD^
deletes the files which were added . Isn't there some way to undo an add