Recently changed Stages Gen II battery and after battery change was getting 30-60s dropouts. Figured it must be the battery as with original battery never had a single dropout in 6 months. FYI head unit is Garmin 500 mounted out front on a road bike.

Google search shows this is a known issue - the battery cover doesn't quite provide enough pressure so the battery may momentarily not touch the contact, especially on a rough road. Not sure if this may be related to CR3032 battery manufacturing tolerances as well i.e. maybe some brands are slightly slimmer? This issue is acknowledged by Stages who suggest either prying the contact up slightly (didn't want to do that in case I broke it) or inserting a shim under the battery cover.

Have found a neat way to shim. I wanted something with a little 'spring' in it rather than something solid so as to not damage the battery cover. Bottoms of soda (soft drink) cans are slightly convex. Simply cut to fit, about half the diameter of the battery cover worked for me and then a small piece of thin tape to hold in place onto the battery cover. Battery cover now a tighter fit but can feel the 'give' in the small convex shim.

The usual caveats: Worked for me but no guarantee, probably voids Stages warranty, undertake at own risk.