I've been playing my new M!x (Spacey Ver.) for a few days now and made it through the first generation just fine- I was able to hatch a new baby tamagotchi after my first was full grown and married.
It hatched, I immediately started caring for it to keep the hunger/happiness bars up. 8:00 PM hit and the baby went to sleep. I put it down and went to do some house stuff for a little bit when my partner brought it to show me that the baby tamagotchi was sick? It was in bed, but it aged to the next level (toddler) and it had the floating skull above it :-( I wasn't able to access the medicine or any other options, I just kept receiving some kind of urgent message (something with an exclamation point at the end-probably telling me my tama was asleep? idk)
I couldn't find any information on this so I panicked and reset the time so I could wake the (now) toddler tamagotchi up and heal it/bump its bars back up. What the heck happened here? Are some just randomly prone to dying at any time?