Line spacing change set line-height to 0 outside of subselection in this SVG2 autoflowed text (and more erratic text layout)

Summary:

Chaotic modification of the last embedded text box after saving, closing and reopening the master file. Erratically alters line spacing and typography, significantly altering its presentation.

Steps to reproduce:

• Open Inkscape
• open sample file Example-File-Origin.svg
  • 
• Select the first paragraph
  • 
• Change line-height to 1.15
  • 

Further erratic changes in line-spacing can occur doing the following (not consistently occurring):

• Create a text box
• Save file and close
• Open file
• Duplicate text box
• Modify the content of the text box without changing the spacing or typography
• Save file and close
• Open file

What happened?

The text box appears altered with zero spacing and modified font size outside of selection.

What should have happened?

• Only selection modified.

The master file should be able to retain the same spacing and font of the text box.

Sample attachments:

• Example-File-Origin.svg
• Example-File-Final-Bug.svg

Screenshots for the second/original issue

Version info

It happens in all versions from 1.1. to development version 1.2. I have been detecting this error since the possibility of changing the line spacing from the top toolbox was added.

Inkscape 1.1.1 (3bf5ae0d25, 2021-09-20)

GLib version:     2.70.0
GTK version:      3.24.30
glibmm version:   2.66.1
gtkmm version:    3.24.5
libxml2 version:  2.9.12
libxslt version:  1.1.34
Cairo version:    1.17.4
Pango version:    1.48.10
HarfBuzz version: 2.9.1
Poppler version:  21.08.0

OS version:       Windows 10 2009

Inkscape 1.2-dev (a6038c51, 2021-10-22)

GLib version:     2.70.0
GTK version:      3.24.30
glibmm version:   2.66.1
gtkmm version:    3.24.5
libxml2 version:  2.9.12
libxslt version:  1.1.34
Cairo version:    1.17.4
Pango version:    1.48.10
HarfBuzz version: 2.9.1

OS version:       Windows 10 2009