"name 'FreeCAD' is not defined" error when selecting workbench, conflicts with Cables workbench

[LeGuipo]

I just tried that workbench for the first time today.
I get the error when selecting the workbench for the first time during a FreeCAD session. It does not appear after retrying. No toolbar nor workbench functionalities ever appear.

After reading the log, I noticed that "Cables" was mentioned. So I uninstalled that workbench, restarted FreeCAD, reselected Optics workbench, and then no more error.

The Cables workbench works fine while Optics is installed. So I report the issue here first. My guess the error is caused by a module name conflict.

Optics version 1.3.9
Cables version 0.3.7

journalctl output :

systemd[1412]: Started FreeCAD - CAD Application.
FreeCAD[64302]: name 'FreeCAD' is not defined
FreeCAD[64302]: Traceback (most recent call last):
FreeCAD[64302]: File "/home/meuser/.local/share/FreeCAD/v1-1/Mod/OpticsWorkbench/./InitGui.py", line 31, in Initialize
FreeCAD[64302]: from examples import example1, example3D, example_dispersion, example_candle, example_semi, example_hierarchy3D, example_energy
FreeCAD[64302]: File "/home/meuser/.local/share/FreeCAD/v1-1/Mod/Cables/./examples/example1.py", line 16, in
FreeCAD[64302]: App = FreeCAD
FreeCAD[64302]: QIODevice::read (QSslSocket): device not open
FreeCAD[64302]: _pythonToCppCopy: Cannot copy-convert 0x6aa0c55993a0 (NoneType) to C++.
FreeCAD[64302]: QIODevice::read (QSslSocket): device not open
FreeCAD[64302]: QIODevice::read (QSslSocket): device not open
FreeCAD[64302]: QIODevice::read (QSslSocket): device not open
FreeCAD[64302]: QThread: Destroyed while thread '' is still running
FreeCAD[64949]: name 'FreeCAD' is not defined