By default if the ClassFileLoadHook bytecodes are for the boot loader, they're not verified so incorrect bytecodes may be loaded. If redefinition is used, then they're verified which leads to confusion. See email thread and reproducer.

https://mail.openjdk.org/pipermail/hotspot-dev/2025-March/102461.html

https://github.com/rjernst/verify-error-repro