on_display_bright /not_bright issues without "always on" display

When the display "always on" option is not enabled, the on_display_bright and on_display_not_bright functions are not being triggered as expected - at least on an LG G Watch R, which is the only device I have.
The on_display_bright function will sometimes trigger when the screen comes on, but this only seems to happen if the screen had been manually turned off either with the hardware button (for watches with one) or by putting a hand over the display - it appears in such cases the screen comes back on in dimmed mode briefly, which probably explains why it works.
The on_display_not_bright does not appear to get triggered at all when the screen goes off.

Since these are the functions in which most animations in the new WatchMaker versions will be triggered, these will only be visible to users who either have the "always on" option enabled or who normally turn the screen off manually.