In order to uncheck checkboxes you must pass "" (empty string) in behat, according with the documentation.

And it seems to work perfectly for @javascript scenarios. In fact it also works passing "0".

But it does not work for ~@javascript scenarios, and the checkbox remain checked both with "" and "0".

To reproduce:

• Install the local_codechecker (master branch) in your site.
• Run the "Verify that the warnings toogle has effect" scenario, it passes.
• Delete the @javascript label from that scenario.
• Run the scenario again, it fails.

Verified under master, probably will fail for other branches too. I've triple looked for similar cases because it really seems to be a common case (wanting to uncheck a checkbox), but haven't found any similar report.

Ciao