I have heard about sensory temperature issues briefly in a documentary, but I think it's so important to share your own experience with parents whose children are affected. (thesensoryseeker.com)
I made it a few times and it was definitely sliceable every time, so I'm thinking it could be cookware (I used a glass Pyrex loaf pan), different brands of ingredients, oven temperature issues (I've checked and mine is correct) or something like that. (connoisseurusveg.com)