Runner at 1st and 3rd with 2 outs. Pop fly center fielder makes what appears to be a diving catch. batter runs hard to first. Getting there as the ball pops out of the center fielder's glove. runner at first heads to second. Center fielder throws to second for the force. Ump calls him safe. Ump argues that since the batter had touched first before the force at 2nd you now had to tag the runner. argued for several minutes but he was adamant. Am i nuts? is there some strange rule no one knows about?