Thank you. Looks like the project is using a version of detekt so old that there wasn't a gradle plugin for it. As a result, it's calling it directly using javaexec. Unfortunately the bold has to manage differences between running Java on Windows vs Unix. Now some of the tests don't pass because of comparisons that I think have line endings. Grrr. WSL doesnt pass all tests either so still subtle differences.
Regretting not spending more for a Mac. Unfortunately can't go 100% Ubuntu as I use some software that's mac/win only..