@anthony_berndt @CASIOJapan At the moment it's just a guess as die is much more complicated than needed for "simple" digital watch. We will see more after comparison to old version.
Yes, quartz crystal will have slightly different frequency at different temperatures: https://onlinedocs.microchip.com/pr/GUID-7084EBB9-C955-4749-8739-6C52B858DEEB-en-US-3/index.html?GUID-99D73706-A33D-4F55-80C9-BBEA97A1FA4D