Weird problem with scores that contain transposing instruments.

Hello,
I am mostly working in the Concertband field (in the Netherlands). My scores always contain transposing instruments. In fact, only trombones, flutes, oboes, bassoons en double bass are non transposing instruments in the Netherlands.
When I finish a score and all the parts the key signatures in the parts are all okay. But in the scores I sometimes see wrong key signatures. It happens random, that is to say, not all instruments are wrong and even it happens that for instance the key signature of lets say the alto sax is okay on the first page of the score but wrong on following pages. When I discovered this in a exported pdf of a score I went back to the piece in question and opened it again in Musescore. But now the key signatures are okay everywhere, also in the exported pdf. So the "solution" is that I have to close a score that is finished, close Musescore and then open the score again.
I can't attach a specific file because, as I said, closing it and opening it again makes the "bug" go away.
I wanted to mention it here as a "BUG"
Greetings, Hans Berkers