UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.67 Safari/537.36

Steps to reproduce the problem:
1. Create a custom mouse cursor with CSS, which alternates on mousedown and mousemove. I use this CSS structure, to create a rotating cursor for a design app. On mousedown and mousemove, I update the CSS class to an another rotation:

rotation-300-degrees {
    cursor: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAYAAABzenr0AAAC8UlEQ…Dl+Pj4cW9v7/e/LnCVwN/PKtsD1wkvOwXXDa8J1BL4JxL4CeHtKDDE4h1rAAAAAElFTkSuQmCC) 15 15, auto !important;
    cursor: image-set(url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAYAAABzenr0AAAC8UlEQ…Dl+Pj4cW9v7/e/LnCVwN/PKtsD1wkvOwXXDa8J1BL4JxL4CeHtKDDE4h1rAAAAAElFTkSuQmCC) 1x) 15 15, auto !important;
    cursor: -webkit-image-set(url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAYAAABzenr0AAAC8UlEQ…Dl+Pj4cW9v7/e/LnCVwN/PKtsD1wkvOwXXDa8J1BL4JxL4CeHtKDDE4h1rAAAAAElFTkSuQmCC) 1x) 15 15, auto !important;
}

2. Verify that the mouse cursor behaves correctly.
3. Open devtools.
4. Viola, the mouse cursor doesn't update. This only happens in Windows and on mousedown and mousemove, works on Mac.

Sorry, I don't have any working example. 

What is the expected behavior?
The mouse cursor should update itself on Windows when the devtools is open and when the mouse cursor is down.

What went wrong?
The mouse cursor doesn't update itself on mousedown and mousemove, i.e. click-and-drag.

I can't really attach a screenshot of it either, since my app removes the mouse cursor.

Did this work before? N/A 

Chrome version: 70.0.3538.67  Channel: stable
OS Version: 10.0
Flash Version: