Is any of this issue fixed by the new syncGoogleSheet() method?
(It could only help when the changes come from a script.)
I think I should have said Library entries when I said Records...
Widgets also fail to update when another user of a shared library makes changes, and also when Tasker, IFTTT, Zapier, etc. make changes, so all of these cases should be fixed. Otherwise, Memento providing a widget on the Android desktop is nearly useless. Second best solution is, as Miles said, to provide a user interface on the widget that triggers an update. (It could be a button, a swipe, a long press...)
I suppose the widget uses some kind of static cache that shares its lifetime of the widget itself, and loads nothing anymore. I simply don't see why it works so. it's not like users need a huge amount of data on their home screen, hence optimization; or the widget has problem accessing the local libraries, the app's own data. If it is complicated for the widget to decide when to update, why not leave it to us? We could do it by, for example, just pressing refresh button on the widget or (preferably) setting the update schedule when adding it.