The content protected by Pay With a Like appears in the RSS feed

We are using the Pay With A Like plugin, but we have the problem that the protected content appears completly in the RSS feed.

We use the button for inserting the shortcut and insert the content to protect in it:
[pwal id="20038338" description="test"] content to protect [/pwal]

We obviously don't want the protected content to be shown in the RSS feed.

How can we solve this problem?

Thank you for your help.