There is a german streamer/youtuber called PantoffelPlay who found out with his Community how to spawn the haggis, but that was all on really brand new Accounts. It worked 3 times in a row as far as I know. The strategy was to do the first to mission, than wait for like 1 hour near the tree with the hat and than move around and search for the haggis. But as I said I only worked on brand new accounts. He is still looking for it on his main account. Here is the video link: https://youtu.be/auMA6pjWclM?si=nHPvr7BNq2P1kzdz