.table > :not(caption) > * > * selector will have to be changed to something more specific.

We are using material virtual scroll so the above selector does not target td/th (we have two extra tags between table and td); so please fix this issue

This selector is meant to scope style to the current table, preventing them to leak to nested tables.

And it also targets valid HTML tables : extra tags in the table structure is invalid.

However not having thead, tbody or tfoot is valid so we need to find a way to support it. Probably something like:

.table > tr > * {}
.table > thead > tr > *,
.table > tbody > tr > *,
.table > tfoot > tr > * {}

@jsgoupil You need JS to drop the tbody since it's automatically added by the browser, isn't it? Why would you skip this feature?
I'm not quite sure about this being an issue at all. Still opened a draft to fix it, but I'm probably against doing this. Do you have any accurate use case that would benefit from breaking a table structure this way?

The HTML specs say that having a tr element inside a table is valid. Now, some browsers will insert a tbody for you if you use plain old HTML tags.
However, if you use .createElement to actually insert HTML tags inside the DOM, then you are technically allowed to add a tr without a tbody.
This is what Angular does (or other framework doing .createElement). I rarely write tbody, so the Angular framework will insert everything without it.
When using Angular, I don't force removing the tbody; it's just not present. I didn't want to create a full blown example of the code here so I wrote a small JavaScript to handle this situation.

In such case, the browser does not add tbody?

Correct.