Option-delete not working in powerpoint
Your question is a little vague because you don't clarify what you deem to be the standard behaviour of using optiondelete.

However, upon my own testing on an iMac with Office 2011, I can confirm that optiondelete within MS Word does in fact behave differently than it does in MS PowerPoint. However, I found that it behaves the same way in both Powerpoint and Excel.

More specifically, in MS Word using optiondelete will delete the entire word behind the cursor in MS Word, while in Powerpoint and Excel it only deletes a single character, just like it would by pressing the delete key on its own.