I noticed a bug that occurs when a duplicate letter is correct, but the word contains only one instance of the letter. In this case, the letter is removed from the pool in subsequent guesses.
Example:
Drive Imply Sitch Finch Cinch _____
The letters I, N, C, and H are correctly placed, but C occurs only once in the word. Cinch was not correct, but on my final guess, C is no longer available as a usable letter.