Pokemon go egg progress color changes

Does anyone know why the hatching progress status for some eggs turns blue of some non incubating eggs, when the Pokemon list sorting is changed? For others it remains black. It seems like sorting the Pokemon list has an affect on the I hatched eggs order, at least sometimes. Has anyone noticed a pattern?

Based on this Reddit post, this appears to be a bug when your scroll from incubated eggs to non-incubated eggs.

This only happens when you swipe between the eggs, incubated to unincubated

I have verified this by scrolling through my eggs and the number will stay blue when I scrolled through at least two incubated eggs.