You do change mbti over time can't you? I tested istj at the start of the year but now it's saying infp
Your functions fluctuate but your type doesn’t change. I tested ENFP, then years later ENTJ, and then ENTP. I did not change from ENFP to ENTJ to ENTP. Your functions take time to figure themselves out. I was an ENTP the whole time! ISTJ and INFP are very different. You may be neither at all.
actually, they have the same functions, just different order. You just need to figure out with your dominant are. At one of these times you may have unhealthly been using your inferior and tertiary functions directly.