Might be able to call and get it fixed, or possibly dispute it, but usually the simpler solution is to just charge a buck on it and let it report a different non-zero balance.
Anecdotally it appears lenders get sloppy and/or lazy about updating balances to 0, especially if it stays that way month over month. Not sure why honestly but enough people have reported it on this forum to push it out of the random issue category.
