FEM: Missing text from reults color gradient legend (due to Font type or Fontconfig)

Problem description

When generating results in FEM workbench, the color gradient legend does not show any text scale beside it:

The color gradient is expected to have some text to indicate the values, as can be seen in the first image from this freecad blog post about the FEM Workbench.

Changing the legend from "Color Gradient" to "Color Legend" by right-clicking the color gradient and selecting "Color Legend" will display text beside the color boxes though:

Note that if FreeCAD is launched from a terminal, the following message is shown as soon as the FEMExample.FCStd file is loaded:

Coin error in cc_flwft_set_char_size(): FT_Set_Char_Size(.., 13, 13, ..) returned error code 23

Workbench affected?

FEM

Steps to reproduce

• Launch FreeCAD
• From the "Start" tab, scroll down to "Examples" and click "FEMExample.FCStd"

Expected behavior

The color gradient has text beside it to indicate the values of the scale

Actual behavior

No text is shown beside the color gradient legend

Development version About Info (in Safe Mode)

OS: Fedora Linux 44 (KDE Plasma Desktop Edition) (KDE/plasma/wayland)
Architecture: x86_64
Version: 1.1.1.20260414 (Git shallow) AppImage
Build date: 2026/04/14 22:09:59
Build type: Release
Branch: (HEAD detached at 0108fd4b4)
Hash: 0108fd4b4850cc46e625b60e53cea7a7bbe69f8d
Python 3.11.14, Qt 6.8.3, Coin 4.0.3, Vtk 9.3.1, boost 1_86, Eigen3 3.4.0, PySide 6.8.3
shiboken 6.8.3, xerces-c 3.3.0, IfcOpenShell 0.8.4, OCC 7.8.1
Locale: English/United States (en_US)
Navigation Style/Orbit Style/Rotation Mode: CAD/Rounded Arcball/Window center
Stylesheet/Theme/QtStyle: FreeCAD.qss/FreeCAD Light/
Logical DPI/Physical DPI/Pixel Ratio: 96/101.6/1

Last known good version (optional)