The EPG on my Hitachi has been playing up the past few days - e.g. the the blue panel which appears at the foot of the screen when you change channel is showing current and next programme from about 6 hours previously - i.e watching a prog at 6.00pm it shows the details of current and next progs which were aired at 12 noon.

There are also a few channels in the EPG which show no information at all and for some reason scrolling to the right to look at later listings seem to just stop a few hours ahead of the current time.
I will also try njp's advice of a reboot and see if that helps.