Yes I can confirm that Nokia Camera BETA, swiped away in the multitask carousel, when launched with the camera button, starts with a Resuming screen instead of a Loading one. My guess is that the camera bits are kept in memory to help with a faster startup but if it's so then the slow startup should not even be happening, considering that Microsoft Camera app loads up instantly from any state.
I've tested the behaviour of the Nokia Camera BETA app on my L830 using WP 8.10.14157.200. This is what I see:
After launching the app, it takes ~2s to load, during which I see a black screen with no message at all. If I
close the app in the task switcher and restart it (launch from start screen or use the camera button), I get the same behaviour, so I'm not seeing the resuming-message like you are. To me it really looks like it's closed and restarting anew, as expected.
If I don't close the app and switch back to it, the behaviour depends on how I do so:
- return using back button: <1s, no message, camera app is returned to previously used state
- return using task switcher: <1s, no message, camera app is returned to previously used state
- return using start screen tile: ~2s, no message, camera app is returned to the default state (no fast resume, seemingly a complete re-launch)
- return using camera button: ~2s, no message, camera app is returned to the default state (no fast resume, seemingly a complete re-launch)
- return from low power state by turning device on: ~2s, resuming message, camera app is returned to the default state (a complete re-launch)
The resuming message isn't an indication that the app was still in memory. It's just telling you that WP is either re-initializing or re-launching the app, but not which one. Still, I agree that the behaviour you are seeing doesn't quite add up.
TBH, I find the inconsistency in this area worrying. Not only can any app override this behaviour, but the default OS behaviour itself changes depending on the type of WP app (WP8.0 app, WP8.1 Silverlight app, or WP8.1 Windows Runtime app).
Either MS royally botched memory management in recent updates or the developers are missing some specific code.
Not memory management, but app lifecycle management. I don't really understand what is going on with the camera app, but I agree that the inconsistencies themselves already make it feel like MS botched something, or is at least letting developers get away with botching app lifecycle behaviour.