[Zubersoft]

Now that I think about it, if you transposed to F, it should be choosing Bb based upon my code. Are you using the transpose by key setting or transpose by steps? I just created a song with your exact chords, set the key of the song to C, transposed from C to F, and it worked as you would expect. Dm, F and Bb were used. I also tried it when transposing by steps, and that also worked. What key did you choose for the song?

If you are using a minor chord for the key of the song, there are still bugs present with transposing with minor chords that won't be fixed until the next update is released.