Children can die now?!

Sooo I'm starting a legacy challenge and on of my sims kids just died from overheating?? I got the life and death pack and I dunno if that's what added it but I'd assumed kids were, like, immune to death.

(My sim has, like, 5 kids if your wondering how I missed this.)

I mean, I don't plan to load a save or reverse this because the story potential is just too good but all the same.

Dang.

Update: so like after posting this I chose to let the dead child remain with the household because, y'know, why not? Except the ghost child doesn't look like a ghost? And I cant put them to rest? I'm assuming this is a glitch?