Stem horizontal alignment differs in score and part

I have a stem going down from the middle of a diamond notehead in the score.
In the part the stem shifts and is no longer centered. If I change this in Engrave>Nothead Sets to be correct in the part, it becomes incorrect in the score.
Any idea why this is happening?

Unfortunately there are problems with creating offsets for noteheads relating to using a different staff size; you will find that the stem attachment matches the editor pretty much exactly at rastral size 3, but if you use a larger or smaller staff size, there will be some inaccuracy in the stem placement.

As it happens I’ve been working on just this problem in recent weeks and it will be fixed in the next (major) version, but there isn’t a good workaround in the meantime, I’m afraid, aside from using the same staff size in each layout, which obviously may well not be practical. I’m very sorry for the inconvenience caused.

I am just guessing here, but the following might work: as a workaround you could use the same staff size in part layout and score layout, but then increase the page size of the score to a virtual bigger size. Finally export the score to a pdf file. From there it will render down correctly if you choose the initially desired page size for the score.
Sorry for my clumsy language…