Is it a problem at all and should we fix it the same way as we fixed T42812?
Other thing we can do is probably redo TOC on .mw-collapsible. However, labels in .mw-collapsible and in .toc are not the same.
Visit the table of contents on desktop
Confirm that the table of contents does not have any visual change (to the heading) during the loading of the page.
"Contents" should not jump to the left on page load (gif shows broken and fixed state)
Please test in IE8, IE9 as well as the usual browsers to confirm.