W3C Jigsaw fails on invalid CSS

I've been running a variety of site analytics tools against my site, https://poochkingdom.com, and I've noticed a lot of validations are failing on invalid CSS that's provided in the templates. I wanted to double-check the issues using the W3C Jigsaw tool, and after a bit of head scratching about parse errors, I realized that some of the CSS selectors are incorrect when it comes to media directives.

Question 1: If I understand correctly, shouldn't the "@media" block be outside of the selector? Should I open a bug for this or will browsers ignore the error?

.fe-block-yui_3_17_2_1_1718560167175_52219 {
    grid-area: 25/3/30/9;
    z-index: 5;
    @media (max-width: 767px) {
    }
}

Question 2: I've seen some CSS shared on the forums using "@media" and borrowed some for my site. Jigsaw is saying the syntax is incorrect until I add the 'only' qualifier. Is this because Jigsaw is out of date, or because this syntax is out of date? I haven't found a definitive answer online.

Parse error @media screen and (max-width: 575px) ....

Parse ok  @media only screen and (max-width: 575px) ....

Thanks in advance.

Thanks @Lesum I'll open a bug to ensure it is tracked.

FYI @Lesum, support were particularly uninterested in opening a bug for this. The support representatives (multiple) were hung up on the fact that the invalid "@media" directive was discovered using tools like W3C Jigsaw. The general sentiment appears to be, "Squarespace is a CMS, so tools like this can't be trusted to give accurate results. Consequently, we're not going to investigate or open a case." They even went as far as saying that they had no escalation path for a report like this, so they take it that engineering are not interested in having them reported 🤷‍♂️

Even including the offending CSS snippet in my emails did not convince them. I guess that reporting bugs is passé.