For the first time, last week when it was about -3c, I could not open by boot. (Not the coldest it been out in either)
The press button for the boot, felt frozen solid and after a few hours of driving, it loosen up but it still would not make that sound to say latch unlock.
So I popped into my Subaru dealer (boot switch was now working) and had a quick word with a mechanic - solution, pour warm water over handle above latch to loosen electric switch up.
Since Subaru XV 2018 models have no other way of releasing the boot; not via key fob and there no boot release handle inside either, this is big concern if that button breaks!