Created attachment 176510 [details] reduced test case The red border around the anchor tag should encompass the div which is parented to the anchor tag. The region returned by absoluteClippedOverflowRect is only for the text that is a direct child of the anchor. The div, with it's size and text is neither underlined nor is it encompassed by the border.
The rendering seems to be similar to Chrome Canary 116, Firefox Nightly 116 and Safari Technology Preview 171. I think we can mark this as 'RESOLVED CONFIGURATION CHANGED', CCing Alan for his input.