I don't know, I use boost and hardly ever use a PC or web interface for Lemmy, and I haven't noticed
In my UI (boost default except for fonts and colours) all I see is total votes for comments ~~, and I can click to see up/down counts on posts~~ *turns out I can't see up and down counts at all in boost
I just logged in on Connect for Lemmy and that is the one that shows up and down votes :) I think I had to turn that function on
So it's pretty random whether someone sees just the sum
Also aussie.zone doesn't always seem to fully synchronise with all the instances I visit, sometimes scores don't load, sometimes votes from some instances don't show so I often see everything with apparently zero votes
*Just twiddled the settings, comment score split is only shown in Connect if you turn on comment debug information, so I presume everyone on Connect is only seeing the sum