Again, &c. So far from the transition from Psalms 107:38-39 being "inexplicable", or Psalms 107:40 being an "interpolation", the perfection of the repetition of the subject ("judgment") is shown by the Structure above.
Related Commentaries of Psalms 107:39
Psalms 107:39
39 Again, they are minished and brought low through oppression, affliction, and sorrow.