Has anybody experienced this problem before?

Yes, and that was the first thing I looked at. The battery was 1 bar from the top. The difficulty going into EV seemed to be speed related (message). Came to a full stop at a stop sign, tried to engage EV and nothing. Started out real slow about 8mph, still no go. Drove to about 30mph, came to a stop, tried EV and it engaged. Got to 23mph and EV went off but ECO would not come on. Went a little further, pushed ECO and it came on. I am not worried about it. I am sure we will get these little glitches once and awhile. Like somebody said, it's a computer.