NoClassDefFoundError on ValidationException with TeamCity Kotlin DSL

When running settings.kts in IntelliJ I get a NoClassDefFoundError on ValidationException. This makes debugging harder as it hides the real issue. I took a look inside the jar and indeed I can't find any declaration of ValidationException, I don't know if it's because it's missing or because it's somewhere else.

This is with Kotlin 1.4 and TC 2021.1.1