BOOX added a new setting called "App Freeze" that most users should disable (they did this to save power, but it's not a great idea to have it default to enabled in my opinion). If that option is enabled in the tablet settings, it will just kill apps that are put into the background. It doesn't sound like this exactly matches what you experienced, but I want to make sure you have that setting turned off.
The latest version right now is version 3.9.16. I have no idea why you wouldn't be able to start the app immediately if the issue was due to a crash. It sounds like the BOOX OS was doing something entirely different if it wouldn't let you reload the app. I've never seen that happen on any of my BOOX devices (BOOX Max 2 Pro, BOOX Max Lumi or BOOX Tab X).
Mike
The latest version right now is version 3.9.16. I have no idea why you wouldn't be able to start the app immediately if the issue was due to a crash. It sounds like the BOOX OS was doing something entirely different if it wouldn't let you reload the app. I've never seen that happen on any of my BOOX devices (BOOX Max 2 Pro, BOOX Max Lumi or BOOX Tab X).
Mike