FWIW, I see this in safari on my osx laptop as well. It’s slightly different - on chrome, triple clicking the last paragraph just selects the text but the quote reply link disappears. On safari, triple clicking selects the text plus the whole next line and the quote reply link disappears - like the @Mittineague example above.
It’s not a major issue and I haven’t had any complaints about it from my members, but it is one that I experience constantly and I find it annoying. It does seem to be a discourse bug, not limited to chrome.