you need to delete all files that you will find in this path:
%APPDATA%\Microsoft\Windows\Recent\AutomaticDestinations
https://www.howtogeek.com/howto/5245/fix-for-when-pinned-jump-list-items-get-stuck-in-windows-7/
[update 2020.04.29]
Please review below article if you like to increase jump list show items:
Windows 10 - How to increase Jump list items number
