It's not the first time Apple software has encountered issues with daylight saving time. However, like every new product, it is not bug-free. On iOS 7, the Calendar app displayed the wrong time (that was fairly minor). Going all the way back to iOS 4 in late 2010, iPhone users had problems waking up their devices due to the time change. And, the users in Australia seem to be fine with the solution. Owners of the Apple Watch Series 4 in Australia, where daylight saving time (DST) rolled out already, experienced a bug that had to do with the Infograph faces on the wearable.
"The Watch reboots itself repeatedly, as long as the "Infograph Modular" face is active with the "Activity" complication". The watch faces are going to be available only for the Nike+ models while the Nike+ 4 Apple Watch Series will also have the Nike Training Club app and Nike Run Club app pre-installed. After all if you can't trust a watch to tell you the time what is the point of all the other functions?
It seems likely that Apple will need to patch this issue before daylight saving time ends in Europe on Sunday, Oct. 28 and in the U.S. on Sunday, Nov. 4.
This was the reason for the failure of Apple Watch Series 4. Apple has not released a statement concerning the problem yet, but they will most likely come up with a fix quite soon. Presumably a new watchOS update can be rolled out before daylight saving time comes to an ends in Europe (at the end of October) and in the USA (at the start of November).
It is one of those rare programming feats where not only am I certain that it is possible to get right, I have done it on a Commodore Pet - which had considerably less processing power than an Apple Watch.