I have now twice had this happen and the first time I thought I had made a mistake but the second time I checked before my ride if brightness was set at auto mode. And for the second time during my ride I get the battery low warning and I see that the brightness is now set at 100% in non auto mode. It looks like this setting is changed by itself. I didn't even touch the device during the ride as I use my remote.
I haven't noticed this problem but an idea comes to mind. When I turn auto off, it reverts the the last brightness level I had set. If you manually set some low level, perhaps it will revert to that instead of 100% when auto spontaneously turns off. If low enough, it should be evident while riding and wouldn't drain the battery as fast. If it works, it's certainly not a fix but perhaps a tolerable workaround.
Good tip, I had already thought of that and set it to 10% last time, but somehow it became 100% again. This may have happened during the firmware upgrade so I have some hope it will stick this time.
