I ran ZG Monday night.
This morning about 15min after raid reset I went back to ZG and as soon as I zoned in I was saved to the same ID from Monday night.
I confirmed I had no instance lock when I zoned in.
I immediatly zoned back out and relogged, no change, not a visual bug.
When my hunter zoned in the same thing happened except I actually received the prompt asking if I wanted to be saved to a 9/10 instance. This did not happen on my mage.
I now have a 3 day ZG lockout for nothing.