Atkinson cycle question

[vskid3]

I noticed something similar a couple times in my Escape Hybrid. It was cold, under 32F, and while using cruise at 60ishMPH, the charge/discharge gauge would switch back and forth every 30 seconds to a minute. My mileage would go up and down accordingly. I'm pretty sure it was doing this to warm up the battery, as I only noticed it when it was really cold.
Your situation could be something completely different, but if it only happens when its cold, it would be a place to start.

[Recumpence]

nope, nothing to do with battery state of charge.