Parameter specified as non-null is null: method biz.ganttproject.lib.fx.TreeTableCellsKt.createIntegerColumn, parameter name

[sycoforbidden]

In Windows with the full version of Java 21 JRE and GanttProject 3.4 Beta III, when trying to start the program with the bat file, i get the following error:

Parameter specified as non-null is null: method biz.ganttproject.lib.fx.TreeTableCellsKt.createIntegerColumn, parameter name

The only modification made to the bat file was, at the start:

@echo off

SET GP_HOME=.

SET "JAVA_COMMAND=%GP_HOME%\jre-21.0.10-full\bin\java.exe"
::IF "%JAVA_HOME%"=="" SET JAVA_COMMAND=java

(...)

I tried placing the main folder in C:\ to no avail.
CWindowssystem32cmd.exe.txt

EDIT:
Version ganttproject-3.4.3390 - no issue
Version ganttproject-3.4.3391 - Issue
Version ganttproject-3.4.3392 - Issue

EDIT 2:

PERT chart is also not working in version 3.4.3390

CWindowssystem32cmd.exe.txt