Curly braces in Leland, Bravura, MuseJazz and Petaluma wrongly scaled when staves are hidden

Steps to reproduce:

1) For comparison, create a score with two staves per system (using Leland, Bravura, MuseJazz or Petaluma).
2) For showing the problem, create a score with at least three staves per system (using the same font).
3) Add enough bars to get three systems, add notes so that the first and third system have exactly two non-empty staves, but the second system has no empty stave.
4) Extend the brace and bar lines to cover all staves of the full system.
5) In Style→Score, hide empty systems (including the first system).
6) Compare the brace width of systems with hidden staves to the comparison score created in 1).

See Piano-3.mscz (score showing the problem) and Piano-2.mscz (comparison score). For screenshots, see the forum discussion on https://musescore.org/en/node/322361.

Expected behavior:
Systems with 2 staves (others hidden) should use the same brace width as the systems in the comparison score (all systems having 2 staves).

Actual behavior:
Systems with 2 staves (others hidden) use the same larger brace width as full systems (no staves hidden).

Reason for expectation: the wish to get a consistent print for a piano piece with multiple movements, one score per movement, most of them using systems with two staves, but one score using mainly systems with two staves, but a single three-staves system for just a few bars.

Workaround: none (as I want to stick to the Leland font).
Currently, this issue blocks me from having the piece printed.

Version number: 3.6.2.548021803.
Same problem with nightly builds for 3.6.x and 4.0 (for 4.0, the problem does not show up until making some unrelated change in the Style settings).

Operating system: Windows 10 21H1

Possible solutions:
A) Keep the current business logic, but allow the user to override the chosen brace width by a property that can be set for the brace in the inspector.
B) Select the brace width per system depending on the number of staves actually shown.

Solution A might be quite nice for a piano score when the user selects the smaller width and gets it also for the few (or only) three-staves systems, but might not be appropriate when grouping instruments in an orchestra score.

Solution B seems to be the better/preferred one in the forum discussion on https://musescore.org/en/node/322361.

But for layout computations with solution B, please take care to use the same layout box width for braces of different width and right-align each brace in its layout box. This is important in order that the first bar lines immediately following the brace align vertically on the same page. Not aligning them would look bad for a piano score with multiple two-staves systems but only one three-staves system on the same page.

Note that G. Henle Verlag uses exactly this layout (larger brace width for a three-staves system, but first bar lines vertically aligned) in piano scores that have some systems with three staves (like Estampes by Claude Debussy).