Juan Tugoh,
No one at any time has said that the rostering on Mixed Fleet is illegal or that they have to have a day off and that includes Litebulbs.
What has been said is that a lot of Mixed Fleet crew had been led to believe that they would get two days off after a long haul flight, like LGW crew do.
Also, many people think that doing a run of long haul sectors with only one day off afterwards would be tiring.