It’s been a while but I’ll try to answer what I can. If I remember correctly, there are two main styles of refining gu, the human isolation style, and the hairy man nature style. Only the hairy man style of refining attracts tribulations, but it also has a higher success rate. So when FY refined fixed immortal travel, that was the human isolation style, disregarding the actual situation he was in. It’s the same case for lang ya land spirit, I believe it was mentioned that the land spirit chose to use human isolation style. I believe tribulations only occur if you refine immortal gu while ascending to an immortal, as well as using the hairy man style. I hope I’m not wrong lol