Correct way to use jack post
Typically, there is a beam put under the joists, then the post are put under each end of the beam. This detail is better suited for longer beams, covering more joists. Somebody has found new and unusual ways do do something there. I can see the logic of what they were trying to do, but makes for a lot of guessing still.

The problem really happened when the insulated pipe was drilled through the bottom edge of the joists.