Message "This is always an programming error ..."

[MichaelFS]

What steps will reproduce the problem?

1. Started JOSM and downloaded an Overpass-Query.
2. After that, the error was shown:

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2025-08-31 14:19:57 +0200 (Sun, 31 Aug 2025)
Revision:19439
Build-Date:2025-09-02 01:30:58
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (19439 de) Linux Manjaro Linux
Memory Usage: 360 MB / 7828 MB (115 MB allocated, but free)
Java version: 25.0.1, Arch Linux, OpenJDK 64-Bit Server VM
Look and Feel: javax.swing.plaf.nimbus.NimbusLookAndFeel
Screen: :0.0 1920x1080x[Multi depth]@60Hz (scaling 1.00×1.00)
Maximum Screen Size: 1920×1080
Best cursor sizes: 16×16→16×16, 32×32→32×32
Environment variable LANG: de_DE.UTF-8
System property file.encoding: UTF-8
System property sun.jnu.encoding: UTF-8
Locale info: de_DE
Numbers with default locale: 1234567890 -> 1234567890
Desktop environment: KDE
VM arguments: [--add-exports=java.base/sun.security.action=ALL-UNNAMED, --add-exports=java.desktop/com.sun.imageio.plugins.jpeg=ALL-UNNAMED, --add-exports=java.desktop/com.sun.imageio.spi=ALL-UNNAMED]
Dataset consistency test: No problems found

Plugins:
+ buildings_tools (36438)
+ continuosDownload (128)
+ reverter (36447)
+ terracer (36438)
+ undelete (36438)
+ utilsplugin2 (36438)

Tagging presets:
+ https://josm.openstreetmap.de/josmfile?page=Presets/Playground_Equipment&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Stolpersteine&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/WifiHotspots&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/public_bookcase&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/BuildingPreset&zip=1
+ /mnt/Daten/Technik/NaviKarten OSM Garmin/JOSM/ChangesetComment2.xml

Map paint styles:
+ https://josm.openstreetmap.de/josmfile?page=Styles/AddressValidator&zip=1

Last errors/warnings:
- 00001.308 W: Fehlende Erweiterungs-Hauptversion in Erweiterung panoramax
- 00001.987 W: Fehlende Erweiterungs-Hauptversion in Erweiterung panoramax
- 00052.811 E: Handled by bug report queue: java.lang.ClassCastException



=== REPORTED CRASH DATA ===
BugReportExceptionHandler#handleException:
No data collected.

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: AWT-EventQueue-0 (52) of main
java.lang.ClassCastException

[GerdP]

It seems you have cut the most important part of the stacktrace. Please attach the complete one.