I am not sure Trump ever spoke specifically enough to say whether this is contradicting what he said. He generally just said things like "I'll protect Medicare" or "I won't cut Social Security or Medicare." General statements from someone who only gives very general statements. But the key is 'currently.' This is the same as what Paul Ryan says: that he'll keep Medicare for those currently on Medicare and even for those a few years from eligibility but phase it out for everyone else who is nearing retirement or folks much younger.
Every sign is that Trump's team and thus Trump is on board with signing off on the bill Ryan wants. Maybe he personally thinks otherwise. It wouldn't terribly surprise me if the issue hasn't been raised with him. But until we hear some evidence to the contrary we should assume this is what he thinks too.