Sorry, it's still pretty glitchy.
I deleted the app and downloaded it again. I then downloaded the April issue (the only one I've played with so far).
On my first try, the thumbnail problem acted as before: it killed the app. Also on my first try, the only items that appeared at the bottom were Issues, Pages, Thumbs, and Menu. Contents and Advertisers were missing. (That had also been the case before deleting the app. At some point those choices had simply gone away.)
On my second try (second time opening the magazine), I hit the Thumbs feature and, instead of touching a thumbnail, I hit the Page button at the top which gave me a page pulldown. I selected a page and the magazine turned to it. After that, two good things happened: the thumbnails worked again, and Contents and Advertisers reappeared at the bottom. And one bad thing happened: the Page button on the Thumbs feature still gives me a page pulldown, but will no longer go to the page. The page is highlighted in the pulldown but nothing happens.
I also have a question about the Contents feature. If I use it, there is a choice of Page and Article. If I hit page, it goes to the proper page. If I hit article, I get a blank screen with the name of the article at the top. I am not sure what I am even attempting by selecting article.
(Ah, perhaps I do see, but it's a different problem. I began to download another issue of the magazine, and it listed all the articles. Is Page and Article to give you a choice of downloading a single page or an entire article? Handy if that's the case, but I'm not sure what it means once you've already downloaded the magazine.)
So, I'm a bit confused.
The app looks great, and I hope we can resolve these initial glitches.