Why did i got D in Tier 5 background check

Hi,
I am a MAVNI applicant enlisted in the Army reserves and I just got my massive (180 pages) background check report.
I have got the following remarks
CASE TYPE SSBI
STATUS CLOSED
CA CM
SC D
F Y

Now, I think “CM” means Coverage met?
D indicated major issues?
What is the significance of F which has “Y”?
What does it means?

I am not too worried because as MAVNI applicant, I am bound to have “foreign influence” like I am a “foreigner” in the eyes of OPM as I carry foreign passport. I am sure that if someone who needs a TS is in contact with me, that would also create a “threat” to person applying for TS. But then the MAVNI program is to recruit foreigners having certain skills.

But I am unsure on this “F” and “Y” thingy?
Does anyone knows what it means?

Per this page . . . https://nbib.opm.gov/hr-security-personnel/federal-investigations-notices/1997/fin-97-06/

The “SC D” indicates that this investigation was “Reopened” . . . I haven’t found anything on the “F Y” . . .