This is an excerpt from the Honeywell Service Information Letter 7 FEB 2011.
(e) Autopilot/Flight Director
NOTE: The following issue affects Phase 5 and Phase 6 only.
1 The radar altitude hold (RHT) mode:
a On some occasions, RHT does not hold altitude and will
increase or decrease altitude without pilot input. This does
not occur every time RHT is engaged.
NOTE: The following issue affects Phase 5 and Phase 6 only.
2 The hover (HOV) mode has been seen to disengage without input
from the pilot. This does not occur every time HOV is engaged.
3 Instrument landing system (ILS) offsets:
a While on localizer (LOC), an offset of as much as one dot off
is observed even though the flight director bars are centered.
This does not occur on every ILS approach and is not limited
to any specific approach.
b If the aircraft is lined up on the ILS prior to engagement,
the offset does not occur.
Honeywell has an software fix which will only be available if you upgrade to Phase 7. However, maybe with more operator's putting pressure on them and Agusta we can have all the aircraft updated.