I don't think it is an unprofessional error, there are many reasons that changes get introduced on the manufacturing line which benefit production speed and/or reduce errors.
What they missed was the after action surveillance and analysis. In a different organization such a change would go in, and at the same time kick off an engineering investigation to verify that it doesn't make anything worse. If that analysis comes up clean, there is no change. If it finds a problem though, then the change is reverted/changed to something else. In regular car companies you see things like "We're recalling all cars between VINxxxx and VINyyyy" which basically delineate that time between when the change was made and the time the analysis suggesting it wasn't a good thing. If its a minor thing there won't be a recall, just a bit of extra "warranty work" at the next service opportunity which the dealer does.
What they missed was the after action surveillance and analysis. In a different organization such a change would go in, and at the same time kick off an engineering investigation to verify that it doesn't make anything worse. If that analysis comes up clean, there is no change. If it finds a problem though, then the change is reverted/changed to something else. In regular car companies you see things like "We're recalling all cars between VINxxxx and VINyyyy" which basically delineate that time between when the change was made and the time the analysis suggesting it wasn't a good thing. If its a minor thing there won't be a recall, just a bit of extra "warranty work" at the next service opportunity which the dealer does.