Strange behavior of GitHub

[Frank H. Ellenberger]

Hi all,

Dmitry watched, that his PRs disappeared from Maint after I merged them
in Master.

So, what happened?
He sent PR 100-104 to github
I pulled them via https://github.com/Gnucash/gnucash-docs/pull/...
sequently into maint, after each calling locally:
(with git checkout maint)
 git pull
 make
 make check

He watched, they did not appear in code.gnucash.org/docs.

I run yesterday locally
 git checkout master
 git merge maint
 make
 make check
 git push

The guides in https://wiki.gnucash.org/docs/{de|ru}/ were regenerated
last night, while *.{epub|mobi|pdf} are still from 2017-07-01. But that
is a separate issue.

Today Dmitry informs me, his commits disappeared from maint on github.
On my machine I have now 21 unpushed commits in maint.

I am clueless, but remember before the last release also one commit
disappeared.

Does anybody whant to investigate in the current state or can I push
them now again?

Regards
Frank