Their positioning in the table is even on the unlucky side.
No one other than Southampton has a better net GD (+4) with a worse point total (33) in the championship. Wrexham is at +5 and 37 points which clocks in at 10th. Millwall is -5 in GD, sports 40 points, and is one spot out of the playoffs at 7th. That's a team that knows it's better to be lucky than good.