If you have a source with a lot of channels (like Pluto which has over 400) and then go into the Android client, manage source, then try to scroll down through the list of channels quickly it will eventually lock up and you can't scroll anymore. You have to back out of the list and start all over again. This makes it very difficult to select favorites deep in the list because you can't quickly scroll through at all. You have to patiently go down a little bit at a time so you avoid the lock up.
Also the channel up/down buttons do not work as page up/down like they do in the guide, this could have worked around the problem.
Running the latest beta, 3.23.117, on a Fire TV (not mobile, using TV remote. Mobile doesn't have this issue).