So, the issue us that on the last day, the temperature drops from wherever it was (usually quite warm) to -5C. This wouldn't be so bad, but the drop causes characters to spontaneously die.
Example: Playing the Roman/Emilia scenarion, on Day 44. Temperature: +17C, Characters (Roman, Emilia, Marko, Zlata): All Hungry, no other statuses. Day ends, and I skip the night. Upon Day 45 (Curb on Crime), Zlata had died from being frozen to death, and the temperature is now -5C. Needless to say, I was not particularly impressed.
This is one of two things that I have ever encountered that squanders an otherwise excellent game, and the other bug caused a loot pile in Looted Gas Station, with all of the loot on the map in it, to disappear. On another note, I have experienced this temperature drop multiple times in the past, and it only occurs on the last day, and from my experience only seems to occur in pre-made scenarios - my custom games have yet to have this problem. The vanishing pile, however, has only happened once, and was merely an unfortunate setback.
EDIT: It seems that this bug does indeed occur in pre-made scenarios, evidenced by the following video: https://youtu.be/1l8fD2CAwWA?t=48m12s
I hope that this can be addressed soon.