The Good News first...

The Mini TES temperature reading do indeed show temperatures higher than 273 K on some of the dusty patches in sunlight.

But before you start your triumphal march, the Bad News...

I'm told that modelling of the thermal response of these dusty units shows that they could NOT reach those temperatures if they contained appreciable quantities of brine or purer water, due to the thermal inertia and conductivity of water.

So, you cannot have your cake and eat it.

(And don't go screaming, "I was right" about the temperatures, since you were right for the wrong reasons, which is almost worse than being wrong!)