Offline Mode did not work today despite being logged in

This morning, I loaded up Presenter at home (already logged in), and checked everything was working and all the service details and media had downloaded.

At church, there is no internet connection / wi-fi, and mobile data is almost non-existent.

So, since I was logged in this morning, I expected Presenter to offer to work in offline mode (as has done for the last few weeks), but instead the app gave a message "No network connection. Please connect to the internet and relaunch Presenter."

I never log out, I only ever close the app. In this case I think the laptop turned off without going through shutdown (it instantly lost power). But still, I have always been logged in before and never log out. It's not good if I can't rely on the app to work when I actually get to church!

Why did this happen? How can I prevent it from happening? Is there anything I could have done, given that mobile data is unreliable. Could this be a bug that needs fixing?

When I got back to wi-fi later today it did ask me to login, so for some reason it had logged me out, even though I didn't log out myself.