On my laptop with Windows 10, 2 thumbnails are missing in the task bar. The 2 applications are pinned to the taskbar but the thumbnails are not visible. To be more specific. It's the Edge and Store thumbnails.
The empty spaces in the task bar show where icons are missing
Your question is unclear. If I understand correctly, you are saying that your Edge and Store thumbnails are not displaying correctly and instead you have a broken thumbnail in place.
You probably just need to rebuild your icon/thumbnail cache. Here is an article on how to do it;
http://www.thewindowsclub.com/rebuild-icon-clear-thumbnail-cache-windows-10
