This is happening if Excel file is with Link Sources.
In attached project you can see very simple code (open file, save file) and there I am using version 19.7.4 which should resolve the problem but unfortunately problem still persist.
As XLS files are damaged would be appreciated to get help urgently.
Good to know that your issue is sorted out by the new fix. Feel free to contact us any time if you have further queries or comments, we will be happy to assist you soon.