I was wondering because I had the same problem with vs_5_0/ps_5_0 and 4_0 a while ago, I had to simplify the shader to stay below the instruction limit, but I lowered it to 4_0_level_9_3 and that did work. I haven’t tried 4_0 or 5_0 since 
I created a topic too, but no solution… I didn’t try a younger version of MG then. Maybe I can find the commit that changed this, if this is the same issue I had.
If your shaders are simple enough you can try to target a lower profile, but I guess you’re using SM 5 for a reason?