I Take Metformin Hal Er 500 Mg My RX Says

I take metformin Hal er 500 mg my RX says generic for glucophage RX 500 mg. mfg anneal pharmacials. The tablet says IP 178. When I take 2 and then eat a meal. If I poop they look like they come out whole within the first 2 hours. How can they be time release if they come out?

Thanks
Pat