When using the new comment editor on my tablet, the on-screen keyboard seems to randomly decide that I'm starting a new sentence in the middle of a word, causing word suggestions to reset and auto-capitalization to suggest a capital in the middle of the word.
Also, sometimes the cursor randomly jumps, the last or before-last space I've typed gets deleted and/or characters from the last two or three words I've typed get hussled around. Finally, the behaviour of the backspace button when held down is unpredictable and can mess up more than just last three words.
Confirmed on: Feedly's built-in browser and Chrome, both Android
How I'm coping: I find that the editor works well enough when I disable gesture typing and all text-prediction features on my keyboard, but that's less than ideal.