If the same letter appears twice in a guess, only the first occurrence is colored green or yellow

[vmenkov]

Suppose the secret word is FLAIR, and the player enters RALLY as his guess. The letter L is present in the secret word, but neither of the two occurrences of that letter in the guess is in the right position. So, logically, both Ls in RALLY should appear in yellow. However, it is not the case: I see the first L (position 3 in the guess word) as yellow, but the second one (position 4) as blue!

Similarly, in the following example MOORS or BLOOM in the example above, only the first O is shown as green or yellow the second one is blue, although yellow would make more sense.

[octokatherine]

This is intentional. It originally behaved where both letters would be yellow, but that confused people by making them think it appeared twice in the answer.