Welcome to the forum. Could you post the song, or an image of the notation? When you reply, look for the File Manager link, lower left, just above Mark as Edited. Or post a link to the song stored in a public Dropbox folder.

Those are called courtesy accidentals and we would need to see the song to be sure what’s happening.

What year and build of BIAB for Windows do you have (Help, About).

You say you set the key signature to Db, which is good. When you did that, did you use the key in the left column or the right?

Is a transposition in effect?

Could there be a flatted note of the same pitch earlier in the measure, perhaps in the bass clef stave?



BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.