Scrollbar variable doesn't work

I found a bug in the scrollbar background variable on Windows. Setting it doesn’t do anything, but applying the related selectors from app.css again in a snippet makes it work.

/* I should only need to set this*/
body {
  --scrollbar-bg: blue;
/* but these are needed for it to apply properly */
body:not(.native-scrollbars) ::-webkit-scrollbar {
  background-color: var(--scrollbar-bg);
body:not(.native-scrollbars) * {
  scrollbar-color: var(--scrollbar-thumb-bg) var(--scrollbar-bg);

The same bug occurs in 1.1.9 still. Why was it moved to the bug graveyard (yet it’s still tracked)?