The attachements I've lost in HG were totally destroyed at the ORIGIN- Osgrid, not lost, just destroyed, and the way it happened was: If any time on a HG tp I CRASHED on another grid, locked up and had to force quit, or the viewer simply quit suddenly, when I logged back into Osgrid again and go to wear the now missing parts, I could SEE them listed in my inventory, but when clicking on them to wear or rez, the console would error with a message about the object not being found, even though I could see the name of it, and the UUID number, nothing I did was ever able to bring the item back. It didn't matetr if I cleared caches, switched viewers, restarted my computer or even emptied the region caches and restarted my home region- the items were simply GONE.
Some of the items so affected included my av's entire head, body parts, radar hud, items one might consider clothing or accessories. It was frequent and consistant enough I wound up making multiple backup copies of my complete AV because I knew that every time I HG tp'd if I crashed there, I'd come back missing parts.
Maybe it's fixed now, but I would still suggest that anyone who has a valuable AV or one they can't replace, or any attachments that can't be easily replaced- taken them all off and go with a default AV you don't care about.