Yes, 1 August and 4 August have me stumped. Interestingly it says I have discovered 100% of words on 1 August, but I wasn't able to whittle it down to 0. I'm not sure if that just means I missed an opportunity to remove the space somewhere.

Or maybe it depends on the order in which you remove the letters? Just a guess.

August 4 is not solvable with the given wordlist. There is no way to get to a word below 3 letters ("set")