An extension should never be injected into a task

[bmuschko]

The plugin extension should not be injected into a task implementation. That's bad practice. Instead, the actual properties of interest should be exposed as input/output declarations so that they can be handled by Gradle's incremental build functionality.

In the case of this particular task you should have something like this:

private final Property<Boolean> autoDownload;
private final Property<Boolean> autoUpdate;

...

@Input
public Property<Boolean> getAutoDownload() { ... }

@Input
public Property<Boolean> getAutoUpdate() { ... }