That has always been the case. The names of the colours are how they are named in game. The lobby open spots have never indicated names in game.
The best you can do is rename your teams to include short-abbreviations of the names of the colours (assuming they are set).
So for e.g, in Helms Deep games, Team 1 is called "Defenders: Ara/Leg/Gimli/Gam/Theo" or something like that, to show that red is Aragorn, blue is Legolas, etc in the lobby.