Errors while changing Base Colors using IE 11

Steps to reproduce:

1. On IE 11 as Admin edit the default theme (Administer Wiki > Look & Feel > Themes > Customize, from Color Theme section)
2. Click on Base colors
3. Select a heading color (select the color from the slider, click in the square to pick a shade and then click OK)
4. Click on the Save button

Expected results: The changes are Saved.

Actual results: Errors appear (the changes seem to be done in the backend as when the user navigates in the Wiki the Headers color is changed).

In the XWiki console: https://up1.xwikisas.com/#qUNEe6dnMngKr12YeIqE7A

NOTE: I didn't reproduce this issue on Chrome 87