Hard to describe in a title line, but the short take:

I have a contact -- Jane Doe -- in my phone. I've got two email addresses, a cell phone number, and a physical address for Jane. Jane moved and gave me her new address, and in trying to keep things neat, I chose to take it down on the phone directly instead of scribbling it down.

So I deleted her old one, typed her new one in the phone, made sure it was right, and clicked "done" (or "save", or whatever it says). It appeared fine.

Weeks later when I needed it, the address was nowhere to be found. It wasn't on the phone or within her card when I looked in Gmail. Oddly, neither was her old address; all I had for her were the email addresses and phone number.

Is this just a known thing, or does anyone have any thoughts on what happened?