Reply To: Sidebar moved to bottom of the page
without seeing the site, this is like me saying to you ‘my car won’t start – what is wrong, but no you can’t see it”!
suggest you try as a test removing any functions in your child theme functions file to see if one is upsetting it, and if so put back one at a time.
If that doesn’t work, do the same for style.css – ie take out all styling and re-introduce.
If neither of those work, then suggest you look to your theme supplier or docs for anything you need to do in a child theme to make it compatible with the parent.