Scenario: A commercial jet goes to take off from a runway (major
airport here in the US), gets halfway down the runway with engines
going strong and then slows down and taxis back. It goes back around
again for another try and the captain comes on the intercom and says
there was "a problem with the trim", and then they attempt another
takeoff which goes fine.

Does this sound ok? Sounds to me like they forgot to do something the
first time around - I mean, if there HAD been a problem they would've
grounded the plane, right?