Android version 5.1.1 on Note 5 with Verizon that replaced my Note 3, which didn't have this problem. With the Samsung keyboard and predictive texting on, I select a word and the Remove text box opens and I click ok. It always responds by saying the word is removed. Most words disappear as they always did with the last phone. But I have found many words don't go away, even done repeatedly. Also, email addresses are included now in the predicted words when they weren't before with the Note 3, same Android version. Some of the pesky words show without prompting when I turn on Incognito. Have tried several solutions, including turning Predictive text off to clear the dictionary, but the words remain when I turn it back on.