Possible symlink time of check to time of use race condition
Gitlab allows symlinks in the deployed pages tree.
lrwxrwxrwx 1 git git 34 Mär 4 16:57 gitlab/shared/pages/kernel-team/kernel-handbook/public/index.html.en -> ../kernel-handbook.html/index.html
As the pages tree is replaced with a new tree, the symlink checks in gitlab-pages are prone to a time of check to time of use race condition. The symlink check can run on the previous tree, the open on the new tree.
As symlinks are not allowed everywhere in the pages tree, just dropping them during extraction would be the easiest solution.