I have off the chart high levels of both b12 and folate, with low ferritin. in a blood test. i was told long ago i cannot process folic acid well. now i take it with methotrexate. could this folic be the cause of these results?

I don't know what you mean by "off the chart high levels" - actual numbers would be more helpful. High blood levels of folate are not a concern for most healthy adults. Still, consuming excessive amounts of folic acid from supplements can be harmful. High intakes of folic acid may mask a B12 deficiency, but I don't know of any way that taking folate would increase B12 levels. Ask your doctor.