This evening my automation to turn on lights 1 min after sundown have failed to fire. Instead it indicates it will fire 1hr and 44mins later than expected. My date & time on the system clock in HA is showing the right time. I wonder is this a coincidence or a taste of things to come 
. Looking forward to see what happens overnight and what new thing I will learn. 
1h44m? Coincidence, or maybe your automation has a bug that makes it take the sunset of the next day into account, rather the one of the current day.
Yes, I suspect you are right.