I am not aware of any automatic crossfeed valve selection. To my knowledge crossfeed valve operation is a manual selection only.
So it could well be an only Airbus thing, which does not apply to 777, when all AC bus fail, one single fuel pump remains powered and therefore crossfeed valve automatically opens ?
Regarding the ice build-up fuel scenario, I’m very septic that the same conditions develop at the almost exact same time in two separate fuel tanks, especially when one of them had almost 400 more liters than the other one.
I don’t know the oil cooler / fuel warmer architecture, but I find it surprising that the restriction occurs into the very spot where fuel should get warmer ?
Also, still no official mention if thrust has been applied after Top Of Descent but before the event and how both engines did react ?