I did a quick Google search but can't seem to find another discussion on this.

I'm flying to HNL on a 767-400ER Micronesia over the weekend. I was originally in 12F but 10F became open last night so I selected it. I got a confirmation and it was successful - the reservation page showed 10F.

But a few hours later, I went back to the itinerary and it showed my seat was 12F again. I thought some GS guy must did something to kick me back to 12F, but what was weird was the seatmap showed 12F open.

I finally called the reservation this morning and the agent told me I was indeed in 10F in the system she uses. She said the united.com hadn't caught on.

Is this a unknown issue? I never had this kind of experience and I am worried which seat I will get when I check in online.