When you query yahoo.finance.options, the volume and open interest fields are not correct for occasions when the amount is above 1000. There is a comma in the number for these instances and the code is just pulling the numbers up to the column. If you look at Google, you will be able to see this.
Sorry, but I just now read this issue but I can put in a fix for this very shortly. Once I've finished I'll submit a pull request.
This issue has been fixed with the completion of this commit a long while ago: thomasdfowler@e28c658