Propagate Part Formatting applying to unselected layouts

I’ve come across some odd behaviour:

When I try to propagate part formatting, it ends up applying to other layouts than just the one I’ve told it to.

In my case, I’m trying to propagate from Violin III to Viola but the Violin II and Viola get changed. I immediately open the dialog again and the Vln II, Vln III and Vla layouts are all selected in the right-hand column. It seems as though it’s only these string layouts that are affected.

Of course, when reducing the project to upload here and reopening to check that I can reproduce… I can’t. I’m merely posting as this has happened before and I have ignored the behaviour.

Has anyone else experienced this?