This occurred on a 29 year old plane. This is almost certainly just a one-off issue. Unless it starts happening frequently with other 757s, it’s nothing to be overly concerned about. And in that case, the NTSB would figure out why it’s happening and issue a directive.

Planes are designed on a “Swiss cheese” model. Swiss cheese (as Americans call any variety resembling Emmental) is full of holes, but you can’t usually see all the way through a block of it. On a plane, something might fail and you can’t always prevent that, but you can make sure that there is enough redundancy that if something does go wrong you’re still covered. For something to cause a plane to crash, the “holes” have to line up so something could pass all the way through the “cheese.”