Haven’t seen discourse on this since it was said to be fixed soon in 2018, but divisi in transposing parts still leads to key signature issues as shown below:
This is a concert Db key sig in an Eb part; top staff displays correctly, bottom one does not. This is reproducible via any divisi in a transposing part, as far as I’ve found. Hope this can get fixed soon, but in the meantime are there any workarounds?
To restore correct key signatures to divisi: before printing, move the divisi and unison tags a little and back in page view. Sadly all the key signatures are lost again when you open the project again.