I was surprised to see Hard/Normal/Easy buttons while playing Favorites. Though I haven’t seen the buttons during a normal review in quite a while, I understand that there they affect the amount of time after which sentences that have already been mastered are presented for review again. But what purpose would they serve in Favorites, where sentences are selected at random? Also, what effect do the buttons in Favorites have, if any, on the review times for the sentences when they come up for normal review?
UPDATE: I think I figured it out. I put some sentences in Favorites that I’ve mastered, according to Clozemaster, but that I know I still need typing hints to figure out. These mastered ones are the ones for which the buttons are shown. Presumably, the buttons come up wherever I see the sentence, whether in Review or in Favorites.
Playing favorites shouldn’t affect next review, so these buttons don’t really serve a purpose in this context. We’ll get them removed. 
Please let us know of course if you’re still seeing the Hard/Normal/Easy buttons, or you notice any other issues.