The US National Transportation Safety Board (NTSB), which is leading an investigation into the incident, said pilots had reported pressurisation warning lights on three previous flights made by the specific Alaska Airlines Max 9 involved in the incident.
As bad as it is if a manufacturing issue caused a piece to fall off an airplane, there's a huge amount of negligence in an airline continuing to fly an airplane that has triggered pressure warnings multiple times without investigating and resolving the issue.