Your temp is a little low and a space heater would probably help.
Cold snakes usually don't get RIs or have any other problems if done correctly.
The cause of them being sick is more human error as in, this snake is too cold so lets warm it up as quick as we can.
If they are cooled slowly and then brought back up to temp over a week or so then all is usually okay.

If it was a new baby, who know what could have been wrong.