@Donald Leckie - One thing we figured out was that if you use your workaround hack, if you are unable to instrument the classloader before the `ThrowableProxy` is used for the first time, you need to tell the JVM not to optimized the method.

-XX:CompileCommand=exclude,ch/qos/logback/classic/spi/ThrowableProxy,<init>

 
Thanks for your help! We appreciate it.

Here's the issue we're dealing with: https://status.gradle.com/incidents/jqh0hrt3h1x4