Delayed flight

Not only were we about 30 minutes late to board the plane but we were taxiing out on the tarmac when the pilot told us that we would have to return to the gate because there was a discrepancy between the head count on board and the manifest. I don't know what the problem was for sure but there were a couple of females who had switched seats and there was a foreign family who were questioned. I didn't see anyone taken off so I think it was just a mistake in paperwork. Touched down about 90 minutes late.