Illinois, like many states that allow write-ins in partisan primaries, sets a minimum number of votes that a write-in candidate needs in order to be considered nominated. Moon Khan, a Democrat, campaigned as a write-in candidate for the Democratic nomination for DuPage County Recorder (no Democrat was on the primary ballot for that office). He needed 844 write-ins. After the initial count, following the March 15 primary, he was told he only had 699. He sued to force a recount, and the recount turned up enough additional write-ins for him to qualify. See this story.
Good for Mr. Khan. Too bad they stopped once he had enough. All should have been counted. It is extremely rare that write-ins are fully counted and reported.