Guessing two of a correct letter will mark both

[tobiasvl]

If you guess two of a letter that only appears in the solution once, both will be marked as being in the word.

[bbbbbr]

This is fixed in my fork:
https://bbbbbr.itch.io/gb-wordyl
https://github.com/bbbbbr/gb-wordle

And also in arpruss's:
https://github.com/arpruss/gb-fiver