Actually seems to be a Homebrew issue but if anyone else runs into it.
For this example (paulixui)
mvn javafx:run
gets the indicated error.
This indicates it should of been fixed at 19.0.2
https://stackoverflow.com/questions/74630535/assertion-failure-when-trying-to-compile-javafx-project-using-maven
I am using a homebrew maven
mvn --version
Apache Maven 3.9.4 (dfbb324ad4a7c8fb0bf182e6d91b0ae20e3d2dd9)
Maven home: /usr/local/Cellar/maven/3.9.4/libexec
Java version: 20.0.1, vendor: Homebrew, runtime: /usr/local/Cellar/openjdk/20.0.1/libexec/openjdk.jdk/Contents/Home
Default locale: en_US, platform encoding: UTF-8
OS name: "mac os x", version: "13.4.1", arch: "x86_64", family: "mac"
Which apparently uses it's own homebrew (Cellar) jdk.
Setting to use the Oracle 19.0.2
/usr/libexec/java_home -v 19
/Library/Java/JavaVirtualMachines/jdk-19.0.2.jdk/Contents/Home
export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-19.0.2.jdk/Contents/Home
and it ran correctly. So the homebrew jdk seems to have missed the fix.