NoSuchMethodError with Gradle 6.0

I’m using a plugin that calls org.gradle.api.tasks.TaskInputs.property.
It worked fine on Gradle versions < 6.0

This method has changed in Gradle 6.0 from
TaskInputs property(String name, Object value);
to
TaskInputPropertyBuilder property(String name, @Nullable Object value);

After upgrading to Gradle 6.0, I now get NoSuchMethodError exception when using the plugin.

If I recompile the plugin with the 6.0 Gradle API then it works.

Is this expected/intended? Do I need to recompile the plugin (surely it will then fail for <6.0 Gradle versions)? Or am I doing something stupid/wrong?