In your case, it actually goes through.
You can trade with an illegal roster as long as you're under a roster minimum and not violating a maximum at a position. Since you are under the roster minimum at TM, your trade will actually go through (it's a loophole, like it is in waivers).
So that trade is actually fine. The issue with an illegal roster is like waivers, you can't go over the roster max at the position or the roster max in general.
Your trade is fine.