To clarify this bug, when the altar is red it suggests that the boss of the champ has been spawned, the altar is not supposed to be this colour as you can see that there are 3 red candles to signify the champ spawn is at level 1 and so the champ boss has not and cannot be spawned at this level. Please see other altars at other champs to see how the altar should look and act.
This is most annoying for those of us who don't "manually" check the champs