Histamine Intolerance /undermethylation can cause a B12 intolerance and folic acid reaction. Please look into this - histamine problems are discussed in the same circles as pyroluria (although I do not think the correlation is understand).
Also, idk how much we can trust all of the tests we take - the body is complex and measuring any amount of anything can be difficult given the fluctuations in your body. Trust your body, use tests when they fit into your overall pattern of health - but my 2 cents is to not try to swim upstream and follow what a test says if your body tells you differently?