Application Status "under review" after 4 weeks into Background check

Hey guys, I am at the end of the 4th week of my background check with an investment banking firm; they've hit a couple of blips in the road with my background check. Initially couldn't verify employment for one of my previous employer (I provided a w2 to confirm) and recently got a call saying I over estimated my salary by $3k...I explained but was told it would have to be elevated for approval. I haven't heard anything since, but went into the application portal and my status was changed from "Interviewing" to "under review". Anyone know what that means? Thanks for your help!