Seat Assignment Question

Hi,
My 90 day window has been open for quite a while. I have 3 sectors on my reservation (VS1/VS4/VS3041). I have been able to select a seat on VS1 and VS3041 but when I try and select a seat on VS4 it says "your seating request has been successful" but when I go back in, it's not there.
I have noticed that VS1 is in 'O' class and VS4 is 'N' class - should this make a difference? FYI VS3041 is also 'N' class but my seat assignment is there.
What am I doing wrong?
Thanks
My 90 day window has been open for quite a while. I have 3 sectors on my reservation (VS1/VS4/VS3041). I have been able to select a seat on VS1 and VS3041 but when I try and select a seat on VS4 it says "your seating request has been successful" but when I go back in, it's not there.
I have noticed that VS1 is in 'O' class and VS4 is 'N' class - should this make a difference? FYI VS3041 is also 'N' class but my seat assignment is there.
What am I doing wrong?
Thanks