Dunno, Nick.
Not sure what may have gone on at Mars, but I do know that multiple plausible explanations of any phenomenum are desireable.
Each keeps the other honest, and pushes the envelope of learning.
Whatever is the result, you have performed a valuable service.
And it seems to me that the timing is also an issue - when various volatile materials were viable in their various phases would seem to still be open.
As Ma Bowser used to tell me - "You dumb SOB, when everyone is looking right, someone has to be looking left!!"
One dogs' opinion.
Arf