Like yours does? It just means he's commenting from another instance than your own home instance. If both you and the other are lemmy.world users and comment on a thread on a third instance, you shouldn't see it.
Right, I see it there. By the way I notice you're using the linkswitcher tampermonkey script, have you noticed it slowing down your browser? I was searching for something yesterday and opened like 30 tabs to review one after another, and my browser was getting laggy as hell. 70% CPU usage and >8GB of RAM. Figured out that it was the script that basically indexed all tabs for potential lemmy links, and I had to kill it in order to get a useful browser again.
I have not had any issues with it, the only two scripts i use is universal link switcher and a modified GM new tab script so any community or post i click on opens in a new tab instead of in the same window. Neither of which I've noticed causing massive lag though.
It could be the mutation observer the script makes, it makes an observer for every lemmy page you are on and that is known to possibly cause lag on some machines.