https://www.w3.org/TR/css-sizing-4/#intrinsic-size-override

The grammar allows the length and auto in any order. Therefore, the following is valid:
contain-intrinsic-size: 10px auto 20px;

However, should it be interpreted as contain-intrinsic-width: auto 10px; contain-intrinsic-height: 20px; or as contain-intrinsic-width: 10px; contain-intrinsic-height: auto 20px;?

@fantasai @tabatkins