ReStack Stacking wrong with grouped Items

Summary:

When using "Extensions -> Arrange -> Restack" the functionality (stacking) no long works properly with grouped items.

Items end up with improper Z values.

Seems to work fine with simple,non grouped objects.

Steps to reproduce:

Create several grouped items

Arrange them so that stacking needs to be done (i.e. adjacent items are not atop the other per stacking)

Select items and select Restack function (Extensions -> Arrange -> Restack)

With default selected, click on "Apply"

Note that items (grouped items) are not properly stacked.

What happened?

Items are not properly stacked per the default settings.

What should have happened?

Items should be stacked per the default settings.

Sample attachments:

This is the .SVG Test file. (Before)

And After:

Version Info:

- Inkscape Version: 1.1 Final
- Operating System: Windows 10 Home
- Standard .msi install