The HEAT doesnt work again... Needs update
I've had some difficulty with that one was well, but I'm not sure an update is needed - sometimes a game restart if you leave it on.
It seems to have some weird effect on knock-down and pilot damage. (seems to negate falldamage on pilot, which appears a trigger for the condition 'knocked down') leave the option on and you have mechs sliding across the ground and making turns like they were standing - even had the same effect occur to my own mechs, can do everything but sprint or get knocked over again, yet instability gauge remains maxed out.
my advice is to make sure you're only using it sparingly - while ordering one of your mechs around, and during a turn during which you HAVE NOT knocked down an enemy mech - or suffered a knock down either. leave the option on until the heat score is calculated by the game (usually it cuts back to your mech after you've had it fire on something to show you the heat buildup, and instead of it going up or red-lining and shutting the mech down, the heat will drop to nothing - this is working on current game patch, and latest trainer. GOG edition.