Hi

Yes both the courses which you are doing are legal

This is because,

One is eligible for pursuing two courses at the same time, the only condition is that one cannot pursue both these courses in regular mode i.e one  course can be in regular mode and other course in distance mode from Open University.

Now, that your Mtech course is regular one or full time and the other course  which you are doing is part time so both are valid, you don't need to worry

I hope that you find this helpful

Thank you