I would not predict that specifically fatiguing the muscle fibers of high-threshold motor units would affect the force produced by the muscle fibers of low-threshold motor units in a subsequent contraction, and therefore alter their levels of mechanical tension.

Once a muscle fiber is activated (by its motor unit being recruited), it produces the maximum possible force that it can. The only things that affect the force it produces once activation occurs are the contraction velocity and its starting length, which are imposed by the external environment.