@mammoth With the 1.6 update, when replying to a post, it places the cursor before the username by default, so you need to move the cursor to start typing. When composing a new post, the keyboard disappears when you select a username from the list. Then, you need to tap the space to the right of the username to get the keyboard back instead of just being able to tap anywhere in the compose area.
Please fix as these 2 things make it very annoying to use Mammoth.