Items vanish (later) when rezzed at/moved to high altitude

Hello, I just recently decided to move my home to 3720m instead of the previous 720. I was in the process of editing, item by item, and simply adding a '3' in front of the Z coordinate of each (720 becomes 3720). As the X and Y of the home's numbers were exactly the same, I thought I had a pretty neat way of zipping everything up there to the new spot. It worked well for a while, since (I rezzed a duplicate of the home). I took a break and came back an hour or so later, and was going to work again, but a friend came over (who doesn't have edit rights on the land or to my items). I noticed that a piece of furniture, and some unlinked items next to it poofed in front of us. I left clicked on a lamp and IT vanished immediately. Then the bed and added pillows went poof, followed by a few random shoes, flowers, and so on that were around the room. They are not anywhere in my trash, or in the sim that I can ascertain. I relogged and a teddy bear (hehe) I had in the room has reappeared. NOTHING was rezzed/moved beyond 4000m, and I am using the latest Release Candidate Viewer. (I have hesitated upgrading to the main one because of all the issues I have read about).
Yesterday I had clicked a prim and it went "invisible" for about 10 minutes, I couldn't see, delete, or edit it, but was able to stand on it. I was told this was some sort of server packet thing. I relogged and in about 5 minutes it came back. The items in my home are not there that I can tell, as I cannot "stand" on or bump into them
Of course nothing is gone that cannot be replaced with similar, but some are unique so it would be nice if possible, and would save me a few L$ in the process. Otherwise I will have to restart from scratch.
If anyone has any ideas or has experienced something similar, please share your thoughts on what you did, I would greatly appreciate it

-Cat Gisel, SL's First (un)Official Hugmonster

Go down to 768 m and look for your missing items.

If you use the old viewer (1.19) to edit objects at high altitude, they snap back down to the previous maximum build altitude.

The ghosted prim is a different issue. Ask your estate manager (or, if it's mainland, Linden Lab) for a sim restart.

[EDIT: Never mind...re-read your post. It's not a viewer issue. But I'll leave this here in case someone with the older viewer DOES have this problem]

Well I meant to add that nothing is back at the old home...and btw the REST of the stuff vanished without clicking, some while I was offline.