Creating score from template with parts ends up with linked staves for multistaff instruments in a part

Save the attached file to your templates folder.

1.) Open it directly; note that none of the Instruments have linked staves (verify in Edit > Instruments)
2.) Create a new score from this template

Expected result: New score is identical to template score with regards to instrumentation
Actual result: Multistaff instruments that are part of a "Part" in the template score end up as instruments with linked staves instead of their normal Grand Staff versions.

Somehow, including an instrument in any part in a template score will lead to that instrument using linked staves when a new score is generated based on that template.