Unfortunately it's not just gmail that's affected. There are a lot of posters on the Google forum reporting the same synching issues (lack of push) with other email apps as well as several social networking sites. I'm seeing it intermittently using K-@ Mail. I just realized I hadn't received any email from my personal acct, pulled down to refresh, and had almost a full days' worth of emails. The work acct also using that app received email normally for part of that time frame but one email from 6:00pm yesterday didn't show till an hour ago.
People already reported that the Gmail app fix didn't clear up this problem, even in Gmail. It seems to be more of a Google services issue?