Even ignoring the super natural elements, soldiers froze in WW1 all the time even long serving one’s.
It’s well documented that tons of soldiers were reprimanded and even executed for such things due to mental health and breaks not being taken seriously and then just being treated and charged with cowardice.
not to mention the countless amount of people who come back from every war with PTSD which can lead to even things like fire works causing them to be triggered and freeze or face other ill effects.