SwiftKey beta version used to be incredibly good. Something has happened to the algorithm, around 2017. it is doing all sorts of very strange things, for example if the second letter of your typing is incorrect it will still try to accept that nonsense word even though the rest of the letters in the word are typed correctly and the only incorrect letter is right next to what would have been the correct letter. For some reason SwiftKey has become more stupid...
Once you choose to not predict a word like "adk" again it should automatically guess the proper word you were trying to type ("ask").
Also, if you put the cursor in the middle of a word to correct it, and then when SwiftKey guesses the word and you tap the guessed word to select it, SwiftKey will enter the guessed word and leave the second half of the incorrect word, so you have to delete that too. Google keyboard corrects this properly, even if you have the cursor in the middle of a word, if you tap on a guessed option, the whole of the previously typed word is replaced, not just the part to the left of the cursor..