So I've just got a notification from IntelliJ that the IntelliJ IDEA 2019.3.1 bug-fix update is now released.
And it says that the Kotlin plugin is incompatible with this build. I'm on 1.3.61-release-IJ2019.2-1 of the plugin.
Is it really the case that Jetbrains have released an update of IntelliJ that doesn't work with Kotlin ?