Numbers appearing in quote boxes

[BlackYeti he/him]

So this is really minor, but the last two times that I've quoted someone it's put a number at the bottom of the quote box when I've posted it.

It's impossible to edit the number out because the number is outside of the editable text field:

Moreover, when I've attempted to edit it out, it's duplicated the number:

Is there a way to avoid it doing this?

[Chaos he/him]

What the. I haven't encountered this. Link me to the posts this has occurred, and mention your browser and OS so I can attempt to duplicate.

[BlackYeti he/him]

And now there's this one too:

My browser is Google Chrome, and I'm using the Windows 10 OS.