It's possible to hide the game posts from Diggy's Adventure by mistake. In the case of such an event, follow the steps below to fix the problem.
1. Go to a profile of one of your Diggy neighbors and find a post containing a reward.
2. Click the arrow button found in the top-right corner of the post and choose the option „I don’t like this post”
IMPORTANT: Diggy’s Adventure and Portal have separate apps, make sure that you have both of them visible and that the bonus you are using for this procedure comes from the app you want to return.
IMPORTANT 2: The "I don't like this post" has been changed into "Report post" just click this instead of "I don't like this post" you are not going to report the post anyway, so don't worry about getting your friend in trouble. This just allows to access the option more easily.
3. In the window pop-up, choose the option „It’s annoying or not interesting” and “Continue”.
4. In the next window, you will see a notification in the middle that you will no longer see the posts from the app in your news feed. Choose “Undo” and confirm with “Done” below.
You will see your Diggy's Adventure/Portal Pixel Federation posts in the news feed again :)