2009Scape Official Forums

It is currently not possible to complete the Pirate's Treasure quest without killing the gardener that appears when attempting to dig for the treasure in Falador Park. Leaving the park and returning to try again causes the digging animation to occur, but nothing happens, not even a "You dig but find nothing" message. Re-logging causes the gardener to reappear when digging. This results in the quest being incompletable for skillers.

Source stating that this should be possible: https://runescape.wiki/w/Pirate's_Treas ... alkthrough

https://gitlab.com/2009scape/2009scape/-/issues/1030 Logged! nice find.

Can recreate in testing FYI, but only if you've not completed the quest once before - a side note of this is the NPC will only ever spawn once, regardless of debug tools.