Recurrence is not a recognized word in my Microsoft Bookshelf dictionary. Re-occurrence is not either so I guess we have to wave our arms mutely if we want to express that idea. Words like this are a recurring frustration to me.
This is actually an English question. Recurrence is the infinitive, non conjugated word. Recurring has -ing at the end, meaning it is being done at the moment. Same difference between run and running.
In mathematics these are different but in English it is the same and only the difference is in the use of tense.
Your question is a language question. It has nothing to do with CARS & TRANSPORTATION, the section you posted it in
Can you explain the difference between recurrence and recurring? Is it "Recurrence Defect" or "Recurring Defect"?
