Was it older than 3 years? Did it have water
in it? Was there any sign of damage?
I have heard of early complaints when they came out that some got water
in theirs. However, that may have also been the hull
nav lights and not the masthead ones.
We had the same one as yours for 5-6yrs without any problem until a lightning
strike took it out. The replacement unit has been without problem for the past 4 years.
Both of the units are used nightly (365 nights/yr) for the anchor
light, and the nav lights are used regularly through the year. The strobe has never been used other than to test it on install.