I solved this.
When you solve one end of the riddle (in either of the two locations), you get a trap door leading to an underground reward area. This area is incomplete (too barren). For the moment there's just a lot of gold there.
To solve this (off the top of my head, as this occurred 3+ days ago):
- pull the levers in the first location in the sequence given in the note found in the second location and vice-versa (pulling a lever in first location affects a column in the second location)
- when you pull the levers in the correct order, a fire will light up above the column.
- When all four flames are lit, a bad guy will spawn and a trap door leading to the treasure will appear
