☆CAUTION!☆ If you click on a link from the comment section you will have to start your current excercise over, even if this is the last sentence in your excercise!☆ I havent been able to find any grammar table either, and I've been using Duolingo for quite some time. I clicked on your link even though in the past when I tried clicking on duolingo links in the comments pages it removed me completely from the current excercise I was on, I was hopeful to finally have a grammar table to go by. Sure enough. It kicked me out. It actually restarted the app! It did not ahow anything else but my Hindi language tree. So to get back here I had to answer the previous 6 questions again. I appreciate you leaving a link; I just wished that it would work! (Not yr fault. Like I said, this isn't the first time, but I felt compelled to let others know that they'll loose their progress). Maybe it works for iphones but not samsungs?
It's not because of the brand of your phone but because of its specs. What you describe lets me think that your phone has little RAM. Going back to the Duolingo app restarted it because its previous state could not be kept in RAM while opening a browser to display the link.