It might be a phase! DS has gone through nap fighting at various times, he's 1yo and I remember at 10mo he was an absolute monkey, took ages to settle for every nap, was just a pain in the bum. Then it settled back to two nice predicable ones, then in the last couple of days we've had some nap refusal going on so it looks like we're moving towards only one... Booooo!
I've got the same with DD, she's nearly 11 months and cut down to 1 nap about 5-6 weeks ago. She was having 2 hours in the morning and an hour in the afternoon, but now has 2 hours at lunchtime. Amazing considering she literally ate and slept for the first 3 months! It was a new phenomenon for me too, DS was still having 3 naps at her age!