If I was using “performance enhancing substances” of any kind (AAS, prohormones, prosteroids, whatever), especially if bulking was my goal, I’d follow the recommended protocol for that substance and adapt my training to suit.
In other words, if your second week of a 2-on Mag10 cycle happens to be concurrent with a planned off-training week, then continue to follow the Mag10 protocol and postpone your off-training week to coincide with an off week for the Mag10.