While playing a scenario, I moved an infantry unit 5 or 6 MPs, when it was fired on. It took some suppression damage, so I rallied it with the rally button. When I rallied it, it got its MPs back allowing it to move another 6MPs (12MPs in one turn is pretty rigorous for an infantry squad). This has happened a couple of times during the scenario.
It's probably a ski unit in the snow. Or it could be a ski unit not working correctly on normal ground. Of course with it being a scenario, anything is possible.
No, I've seen the same thing with standard US squads on August '44 France maps. I only had it happen once and I just thought it was something I missed when I was playing.
But I have definately seen it happen too. If it occurs again, I'll try and get a save.