The investigator and adjudicator are going to look at the facts of the case. This matters much less than the disposition. They will look at the reasons that the charges were dropped and why the arrest was expunged.
Think about it: There’s a big difference between dropping the charges because of an illegal search or lack of evidence and dropping the charges because someone else confessed to the crime. Innocent and not guilty are two very different things.
So, you are the only one here that knows what happened.