It's a patch antenna, what'd you expect? It prefers a horizontal orientation, not vertical as I'm sure you know...also likely affected by being that close to your RF-blocking self & pack.
Yeah, I know its a patch antenna, but geez, after how many years of failure, what does it take for Garmin to do some thing about it? (like a different antenna geometry?)
I can offer a solution for your current GPS at least. I use the carrying case with the belt clip (yes, ironic since if you put it on your belt it won't pick up satellites) and put it on my pack as shown in my profile picture. It is flat and level so the patch antenna works and it gets my body out of the way of most of the satellites.
Glad it wasn't just me. I recently acquired the Legend myself and took it out for the first time last weekend for a good long walk - I intended to transfer the track of a new trail to a topo. Lo and behold I discovered that every time I clipped it to my belt it lost the sats so my track was sadly lacking.
So I jumped on the Garmin web site to order a clip on antenna - oops - they don't offer one. Guess I check into the backpack strap application idea.
Yours aye,
The Prospectors
"Roads? Where we're going we don't need - roads!" Dr. Emmett Brown