no solver back end - not installing on 2023.08.06

[bambukouk]

testing appimage
unable to install solver backend
error message:

06:56:19  1.249316 <asm3.main> init_gui.py(14): no solver backend found
06:58:45  FreeCAD 0.21.0, Libs: 2023.806.0R14555 (Git shallow)
Collecting py-slvs
  Using cached py_slvs-1.0.6-cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (316 kB)
Installing collected packages: py-slvs
Successfully installed py-slvs-1.0.6

06:58:45  >>> >>> >>> >>> ... ... ... ... ... ... 

using:

OS: Debian GNU/Linux 11 (bullseye) (KDE/plasma)
Word size of FreeCAD: 64-bit
Version: 2023.806.0.14555 (Git shallow) AppImage
Build type: Release
Branch: HEAD
Hash: 93dae74dba4a80dba52f9c5fe73fe5a874bae809
Python 3.11.4, Qt 5.15.8, Coin 4.0.1, Vtk 9.2.5, OCC 7.7.2
Locale: English/United Kingdom (en_GB)
Installed mods: 
  * ToolViewReverse_ToolBar
  * DynamicData 2.46.0
  * sheetmetal 0.2.49
  * Assembly3 0.11.4
  * fasteners 0.3.40
  * ThreadProfile 1.81.0
  * Manipulator 1.4.3

I have also checked snap (beta) version and it was perfectly OK...
so, it seems that the issue only applies to appimage version?