End of level choices

Without getting too deeply into the game mechanics, you are intentionally being left with 1 move so that you will buy extra moves or use a booster.

There is an algorithm that decides the pattern of moves needed to win a level. If you deviate from that pattern too many times, the game considers the level lost. At that point the game will trying to leave you with as few additional moves needed as possible to pass the level without letting you pass the level. If you are seeing a single move left, you had already lost the level and the game is just trying to get you to use a booster/buy moves.

Also note that the game cannot always get you down to a single move but it will try.

You might just be in the test group getting that. There seems to be 4 to x versions of extra moves now.

1. 5 + 10 per loss after the first one, boosters in there somewhere.
2. None for a few rounds, depending on level difficulty, then 5 per loss and potential boosters after the first.
3. 5 + booster
4. 5 + 5 and boosters starting on the second "loss"
5. 5 once and no addition moves after

I am sure there are others as well.