We use PDF Export and include image files (png using an img tag (although I tried CSS as well when looking into this issue). Recently we updated to Angular 10 and latest Kendo for Angular packages.
With Chrome there was no issue, but with IE 11, the images do not show up anymore in the exported pdf.
We isolated the change in behavior to @email@example.com - i.e. the images show up using 1.9.0, but do not using 1.9.1 or later versions.