When did Chrome start underlining links differently?

This is a new default in Chrome 64, although supported since Chrome 57. See the corresponding "Intent to Ship" thread in blink-dev (the Chrome web engine's development forum).

In Chrome 57 we shipped support for text-decoration-skip: ink; which allows skipping descenders in underlines (illustration). We initially suggested making it the default in the intent process but dropped this part for shipping because we had assumed a spec change was required.

We would now like to enable ink skipping by default.

Added a quick chrome extension (my first one) to disable 'ink skipping' in links:

https://chrome.google.com/webstore/detail/disables-ink-skipping-in/ibhigfbbjaeadpfgfhjgcoioddhhlbmf

Agreed. It was awful looking at those link interrupted underlines!