Very peculiar bug of sorts - saving quotes

[ShadowMaker SdR]

I don't know if this is related to my browser (Vivaldi recently -so Chromium) but the option to save quote is displaying a very specific bug (almost Konami style)

If there's a mult-line post I like to save quotes from, it's impossible to double click the last line (to completely select it) and save the quote.
The save quote pop-up appears for a very short time and then disappears again, before you have time to click it.

Now here's the weird part: this does not happen in the other lines of posts, only the last one.

Also, selecting parts of that last line by click-dragging *does* work, most of the time. So far the only thing that fails every single time is 'double-click to select' and then save quote.

I can do a screencast to demonstrate, should that be useful?

EDIT: it's both in Vivaldi and Edge, but not Firefox, so it appears to be Chrom(e)(ium) related.

[Midgardsormr]

Confirmed. I see the same behavior in Chrome.