SEVERE: Buffer cannot be destroyed: java.nio.DirectFloatBufferU

Even by adding this JVM arg (which used to solve that on jdk 11+)

"--add-opens=java.base/jdk.internal.ref=ALL-UNNAMED"

you can test it with

Forum post:
https://hub.jmonkeyengine.org/t/jme-on-jdk-16/44411/6?u=ali_rs