Charts doesn't display chords properly when I change key - e.g. C## instead of D

Hi - new user currently checking out all the tools here. I'm having real difficulty getting Charts to display chords properly for some songs if I change keys. E.g. I imported a song where the original Chordpro file was in in the key of C#. It imported fine, but as soon as I try changing the key in Charts it starts doing really wierd things with chords - e.g. if I change the key C# to D, instead of showing chords of D, it displays it as C## (yes you read that right C sharp sharp!). If I change the key to C then instead of Am it displays Bbbm (B flat flat minor). In any key it does wierd things e.g. Fb instead of E, B# instead of C, Cb instead of B etc.

Other tools e.g. Songbook Pro have absolutely no issue getting the chords right with the same Chordpro file when I change key.

Is Charts really this bad and unuseable for changing keys of songs or is there some trick I'm missing?

Think I answered my own question with a bit of experimentation: Chordpro import and transposition in Worship Tools is buggy - and has absolutely zero tolerance for any enharmonic equivalents (i.e. when the same note has different names such as C#/Db, G#/Ab etc.). Chords must be entered exactly according to exact musical theory with no deviations. If the key of the song is a "sharp" key - i.e. the sheet music would have sharps in the key signature (e.g. G, D, A, E, B, F#, C#) then all the chords must use sharps and no flats. E.g. if the song is in the key of E, a chord of E/G# will transpose fine (e.g. if transposed from E to G would now display as G/B), but E/Ab will not transpose correctly (e.g. if transposed from E to G it will display as G/Cb).
Similarly if the song is a "flat" key (Ab, Eb, Bb, F etc.) then all the chords must use flats and no sharps.
Also the key tag in Chordpro has no relationship with the "Default Song Key" in worship tools planning - both must be the same, again with no enharmonic equivalents. E.g. if a song has chords in the key of C#, but the key tag in Chordpro is Db then the transposition will fail completely and do really wierd things. Key tag must be C# in this case.