Pie chart diagram, same autodefined colours v3.36

[korolexa]

What is the bug or the crash?

All colours are the same by default when creating new field to a pie chart (no random/different colours as before).

Steps to reproduce the issue

Get categorized shape file. Properties - Diagrams - Pie Chart - Attributes - Select all (or one by one) +fields.
They are the same colour (blue). Not as expected, each different.

For instance, this tutorial (data in video description).
https://youtu.be/1-tahbxfHGM?t=168

Versions

QGIS version 3.36.0-Maidenhead
QGIS code revision 09951dc
Qt version 5.15.3
Python version 3.9.18
GDAL/OGR version 3.8.4
PROJ version 9.3.1
EPSG Registry database version v10.098 (2023-11-24)
GEOS version 3.12.1-CAPI-1.18.1
SQLite version 3.41.1
PDAL version 2.6.0
PostgreSQL client version 16.1
SpatiaLite version 5.1.0
QWT version 6.1.6
QScintilla2 version 2.13.4
OS version Windows 10 Version 2009 (? win 11 home actually)

Active Python plugins (none, turned off)

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response

[ValentinBuira]

Can confirm, latest working 3.20