[Colin]

Is this a sign that these battery's may not hold up for years to come? I heard its going to cost around 3-4k to replace one if its outside of warranty.

No, the battery they're talking about is the conventional 12v battery and has little to do with the hybrid battery pack. Also, since the Honda battery packs are either 84 cell (CR-Z and Insight) or 120 cells (Civic) the replacement costs are not that high.