The app doesn't crash and the changes appears to save (ie, I can close the app and open it a number of times and the changes are still 'there'). But then I'll open the app again - often several days later - and it has reverted to an old configuration.
Vera support cleared some cache files and suggested that I delete a couple of plugins, which I've done. But the configuration file is saved on the ipad (or dropbox) not the Vera so this 'housekeeping' won't fix the issue.
I also saved the configuration to dropbox, deleted the app, reinstalled it and re-loaded the configuration. This worked but didn't solve the problem.
I've resorted to religiously saving the configuration to both the ipad and dropbox. This has limited the impact of the issue but I'm still losing changes.
Not sure if its relevant but I have quite a complex configuration with 11 control screens - lots of dimmer sliders and on/off buttons and quite a few web tiles.