Strange Rehearsal Mark behavior

So in Staves and Systems, I set up rehearsal marks to appear above Woodwinds, Pitched Percussion and Strings. For some reason, the rehearsal mark jumps down to the Harp part but returns to normal afterwards. Any idea why this is happening?

It must have to do with the vib to bass drum instruments change. Once is pitched; one isn’t.

I’m not saying it should do that, though.

Because you’ve changed to non-pitched percussion at that point?

Put in a hidden note in the Vibraphone and silence it to delay the switch to Bass Drum.