Happens all the time.
The extra at Izumi is probably for an extra thing.
There may be some quiet seats around the outside corner from the climbing walls.
There may be a couple of very forward ones on deck 7 which RCI also considers obstructed. Also, some cabins on deck 7 on Ovation may be listed as obstructed but are not listed as such on Anthem. Obstruction is in the eye of the beholder.