I have a new colorado 300 and have been use a Legend Cx up until now. I have a problem that I think is likely related to the issue you are talking about. First so we are clear I have ver 2.50 and am not really comfortable with moving to Beta software (been burnt a few times, I'll wait)
The problem occurs when we are Geocaching, I do not use the compass to geocache but cache on the maps. The Colorado displays a nice pink line pointed toward the cache but the cache is not at the top of the screen even though I am walking towards it. I have resorted to moving and verifying that indeed the distance to the cache is dropping to verify I am heading in the right direction. I have walked on trails that I know lead to the cache only to have the GPS show me moving diagonally across the screen, following the pink line or occationally even backward which is really disconcerting as you cannot even see the cache on the screen. As you get closer to the cache it's almost a snail shell pattern to close in and find where the GPS zeros.
I have played with the setting and was convince that somehow the tracking was off. I kept trying checking the ensure that the setting track north was not on and it wasn't, north was not always up. I am thinking now after reading this forum thread that maybe the issue is that the compass is indeed turned on and I have never calibrated it.
I will try both turning the compass off while geocaching or even better try calibrating it. I hope this will eliminate the problem and will post back if this does correct it.