Dakota 20 paperless problem

[nutwood]

This is a continuation of a query I first raised on GPS Australia regarding some memory hassles I've been having with my new Dakota.
Basically, I've discovered that some caches that I've downloaded are invisible. By invisible I mean that I can't find them on either the cache or waypoint list, and if I'm close to them they don't appear on any "nearest" lists. However if I connect to a PC and view the files, there they are, and if I try to down load them again I get the "already exists" message.
Now, I narrowed the problem caches down to a particular period, between one battery change and another, and I discovered that over-writing them brought them to the surface. I thought I had it licked as a passing glitch. However, yesterday, I went after a gnome (GA2788). I'd spotted him earlier and downloaded the cache, but before I got there the Triumph Twins had picked him up and moved him 760m. No problem, I downloaded and over-wrote the existing file.
A few days later we went hunting. The GPS lead us unerringly to a gnome hideaway, but no gnome. I put it down as a DNF (what are the initials for beaten to it?). After I logged the DNF I looked at the map for the location and noticed that it showed GA2788 in an entirely different area to where we'd looked. I checked the co-ordinates in the description on my GPS, they were the same as the co-ordinates for the gnome. I checked them against a map. All correct, but still the GPS wanted to take me somewhere else. A quick check showed that the "somewhere else" was the prior location of this gnome.
It seems that when I over-wrote, it updated the logs, descriptions and hint but the basic waypoint location didn't update.
I double checked it all, then over-wrote again. Nothing changed but the distance away reduced by 0.7km.
This all a bit of a worry as I'd like to be confident that when I down-load a cache, it's actually there.
Does this sound like an issue with the Garmin or with software involved in the downloading? Apart from this issue, the Dakota has behaving flawlessly.

[mtrax]

I've had a Dakota 20 for some time now, and I've not had this problem, I would perhaps delete your GPX files and do a system reset to factory defaults and generate a new file.
You didn't say how you were generating file I assume you where using GSAK, did you select Dakota in the GPS setup?

[nutwood]

I think your advice on how to fix the problem is probably sound. My current theory is that, for a period of time, when it downloaded the cache, it either mangled or omitted the actual location. That resulted in locationless files, so of course they didn't appear because it didn't know where they were.
When I updated an existing file (the moveable cache GA2788), it overwrote everything except the location, this file did appear, as of course it had a location, just the wrong one!
I contacted Garmin who thought it might be a firmware option and recommended updating. I attempted this but it appears I have the latest version. I'm going to keep a close eye on it to see if this was a one off event. Since I changed the batteries it's been fine. I keeping a few of the invisible files and if it occurs again I think I'll make it Garmins problem. It's only a few weeks old and I'm fairly sure it's not anything I'm doing. Of course the next firmware update might sort it out as well.
Good GPS apart from this issue. Bit of a step up from my GPS38!