AutoInput Key Suppresses don't work on Samsung Galaxy S3

I'm trying to disable my volume up and down buttons on my S3 when on the charger and in landscape mode

Autoinput Modes
Key Suppress: Disable
Keys: Volume Up Volume Down

For some reason, this task doesn't work. Isn't showing an error in Tasker either.
I've tried enabling and disabling Intercept Keys from within the AutoInput app, as well.
I'm rooted, but to my understanding root isn't needed for this.

Could it be b/c I'm on Android 4.4.2?
If so, is there a workaround for this?

I am getting a Tasker "Broadcast Error - Failed to execute broadcast task" error toast, but I'm not sure that it's related to this task or not...