Unable to remove Button background on hover

I have an IonButton component with the fill set to “clear” and the class isLink on it.
In my css I’m trying to override the default hover background color, but nothing is working. I’ve tried the following approaches:

Doesn’t work:

.isLink {
  --background-hover: none;
}

Doesn’t work:

.isLink::part(native):hover {
  background: none;
}

Doesn’t work:

.isLink::part(native):hover {
  --background-hover: none;
}

If I set the background to “red” instead of “none” or “transparent”, it works fine like this:

.isLink::part(native):hover {
  background: red;
}

What’s going on here? What’s the correct way to override this style?

This is working for me. Here is a StackBlitz - Unable to remove Button background on hover - StackBlitz