The solution to this puzzle is simple. The cube in the far end of the room will show you, how many cubes around the Stellagia pillar have the correct sign on them, when you check their status on Stellagia. So you just have to hit the cubes continuously, check status on Stellagia after each hit and check the far cube to see how many lines and dots are lit on it (1 line - 1 cube, 2 lines -2, 2 lines and a dot - 3, 2 lines and 2 dots - 4).

The real problem for me was that the signs on the cubes were changing without me hitting them. This was driving me nits! The trick was simple though. My pets with aggro skills were activating the cubes and breaking everything for me.

Big thanks goes to the Rexeen R, which mentioned this in his comment here: https://www.youtube.com/watch?v=zrM6_g1de0Y

DISABLE YOUR AGGRO PETS, they move the cubes without you hitting them

That dude in the video solving the puzzle:

www.youtube.com/watch?v=zrM6_g1de0Y