I received this mail yesterday:
I am a student with F1 visa status and filed both federal and state taxes for 2019 and 2020. I do have an external scholarship that includes a very good health insurance. I filed 540NR for 2020 CA tax, and the filing instructions I followed did not say anything about line 91 (health care coverage checkbox), which I skipped. I believe they thought I don't have a health insurance and enforced the penalty on me.
Is there a way to go about this? Shall I contact my insurance or just amend my 540NR? I appreciate the help!