Test nested selectors with @testing-library/react ignores primary

[nkint]

Hi!
Sorry for double posting it here, I'm working well with theme-ui but I'm really struggling in testing theme-ui related behaviour because of an issue with @testing-library/react.

I already asked in the issue #1026, where I setup a basic repository to reproduce the problem: the test seems to ignore "primary" in nested selectors.

I have this component:

    <Box
      ref={textRef}
      sx={{
        bg: "dodgerblue",
        "input:checked + &": {
          bg: "primary", // NOTE: change to "tomato" to pass the test
        },
      }}
      {...textProps}
    >
      {checked ? "Checked" : "Unchecked"}
    </Box>

this theme:

const theme = {
  colors: {
    background: "white",
    text: "black",
    primary: "tomato",
  },
}

And if I test this JSX:

      <ThemeProvider theme={theme}>
        <Component
          checked={true}
        />
      </ThemeProvider>

The test fails because of:

    - Expected

    - background-color: tomato;
    + background-color: dodgerblue;

Can anyone help me in spot any kind of error?
Thanks in advance!