How to change the transparency of a component in hover state?

If I:

1. create a rectangle
2. colour it red
3. make it a component
4. create a hover state
5. apply 50% transparency to that hover state

then in preview mode, should that rectangle turn from 100% opaque to 50% transparent?

When I apply 50% transparency to the hover state, it also changes the default state, when I correct the default state, it changes the hover state! This is driving me insane when it should be so simple!

https://we.tl/t-PqHo7sVp4R

From the file linked, you can see the same settings for a rectangle when part of a group works as expected, but when it is a rectangle by itself, it just won't work. Why?

Can this feature not be applied to a single object? Does it really have to be multiple objects within a component before this works properly?

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