actually, the issue was solved a couple of months ago. Unfortunatly, it doesn’t work anymore (probably due to theme updates).
To put it short, eventhough a post is marked ‘sticky’, it will be pushed down by any newer post.
From time to time, we need that function.
Thanks for your affords and all the best from Germany,
Are you sure this issue is still happening with you? If so, please send me a link to the page with admin login, and i will check it in order to find whats wrong.
Because I have just tested it and it was working normally.