checkAccessModifier fails to serialize unit of work

[sghill]

Jenkins and plugins versions report

N/A

What Operating System are you using (both controller, and any agents involved in the problem)?

Ubuntu

Reproduction steps

Run build with checkAccessModifier enabled

Expected Results

No failure to serialize

Actual Results

09:40:37 * What went wrong:
09:40:37 Execution failed for task ':checkAccessModifier'.
09:40:37 > A failure occurred while executing org.jenkinsci.gradle.plugins.accmod.CheckAccess
09:40:37    > Could not serialize unit of work.
09:40:37       > java.util.ConcurrentModificationException (no error message)
09:40:37 

Anything else?

No response