The egg was not continually incubated through the day. This is not a matter for any great concern at this point. The eggs are hardy to a point and although a bit cool in Norfolk today (Mean Temp of 50 F ) it was by no means a frigid day.
Something had the adult's interest, quite possibly the squirrels nesting just downstairs. They've been active and the eagles are likely responding to to this noise. While gray squirrels are common predators of songbird eggs, eagle eggs are much thicker and would by no means present an easy meal (especially with adult eagle close at hand).
Some have started to question the identity of the male eagle - claiming he "looks different". Some aggression and or reluctance between mates during nest exchange is not uncommon In reviewing many images from today and previous days - nothing was noted that would call into question the identity of the male. With the amount of intra-eagle interactions at this nest concern is certainly understandable.
Now we'll wait and see if a second egg will be forthcoming.