We continue to work on the widgets, but after doing a lot of digging and reading through a lot of documentation our lead developer has come to the conclusion that this is because Android no longer allows us to sync the system clock via services (which is what most of the widgets use). Basically, on those widgets now using the system clock, the app itself has to perform the updates, rather than just showing you what is on your device clock.
The 5x1 clock widget is the only one currently that passes through the system clock (not using a 1Weather service), and from what we've seen, it should stay up to date.
We are working on updating the other widgets to work properly via the same method, but this may require some slight redesigns, as well as some reductions in customization capability. We know that some customers will likely be disappointed with the change, but with more and more restrictions being placed on what apps can do in the background (and even more restrictions coming in Android O) in order to increase battery life, it may be the only way to ensure that all of the clock widgets update reliably.
The newer 5x1 clock widget should work correctly, as it's the only widget that we have right now that uses the system clock.
We are working on updating the other widgets to use the same technology.