You'll also notice that new content being written by yourself or Posts by Friends is not showing up in the Timeline but they are being shown in the News Feed.
You can temporarily view your content here by replacing the words 'PROFILE-NAME' with your Profile's name:
https://www.facebook.com/PROFILE-NAME/timeline/2012/5
To permanently show your content, you have to delete any recently created Interest Lists.
Interest Lists can be accessed as the last set of items on the left hand Facebook panel.
Hover over the word 'Interests' and click 'More'
In the list that will be prompted, click on the pencil icon next to the List you wish to edit
Do this for any recently created Interest Lists. Return to your Timeline and the content will have been restored.
Thanks to everyone who contributed to the conversation at Wall » Wall: Bugs and Known Issues » All of my activity from May has...