We just changed time here in Canada.
Both my 265 and my wife’s 265s (both running sw version 3.56) did not stay in sleep mode last night despite having night mode scheduled properly from 10pm to 8am.
I am not sure when the night mode stopped during the night, but I woke up at 3am and my watch was no longer in sleep mode. The screen light is actually what woke me up, my watch must have been close to my face. Soon after being awaken, my wife moved in the bed and the screen on her watch went on as well.
Sleep mode has been working flawlessly the night before and since we got the watches, it’s never been an issue.
On a side note and for those who might wonder, the sleep mode is better on the 265 than on the Epix gen 2: the screen is slightly less bright at night and in my opinion it makes the 265 more comfortable than the Epix.