I think that a good first step would be adjusting the ratio of its action umbrella and basing its functionality by motion detection only.
This way cloacked mechs not moving would not be rendered on radar, thing which i find to be like pretty coherent (too).
*Fun over realism if you want?
Note ::: IIRC, I've already said it but there's also the possibility of having 2 types of Scanners (at the end):
The current one we have right now coherently revised and a new brand version of it (requiring more slots to be equipped) with wider action umbrella and, why not, even equipped with some extra gear like a little e-shield or even self-cloacking... just an idea though.
Plus the possiblity as you guys suggested above as one longer durability, etc.