Hi, we currently have discussions here among evaluators whether the HTML5 default browser error validation without any custom error validation is sufficient to meet 3.3.1 Error Identification. On fields of type text, NVDA will after submit move focus to the first field in error and just read a non-descript error message like "Please fill in this field" (Firefox, Chrome) or "Required field" (Edge), but not the label of the field (I would assume screen reader users may learn soon to tab one step back and forth again to get it read out, or exit forms more and arrow up, but I am not sure).
Compare https://codepen.io/stringyland/pen/BvMrqb
Chrome does not highlight fields in error and the message disappears after about 6 seconds. It stands to reason that this is a Chrome UA issue - in Firefox, the message remains at least until the next tab. And on tabbing through the form, Edge will show popup messages for all fields in error.

Would you consider the fact that the label of the field in error is spoken by none of these browsers (with NVDA) a user agent issue?

Most of us tend to think (grudingly) that HTML5 native error validation would be a minimally conformant implementation for short forms, but we are less sure whether we can call this a PASS on longer forms when multiple fields may be in error but only the first field gets identified (and incompletely) - and some browsers are not very helpful in the way errors are indicated visually.
Any thoughts?