In general, filing multiple DV based AOS applications without the previous application being rejected/denied is not recommended.
There is a particular case with two applications in the system at the same time, because the first I-485 has an error which should have led to the Chicago Lockbox rejecting the form (since it did not have the required supporting documents for the erroneous selection), but it wasn't. Anyway, the 2nd package was also accepted, payment wasn't cashed for the 2nd package, and I believe this person is going for their interview in the next couple of days or so.