AFI load error with -F flag?

Hi, I have one AFI created OK and I can check out it status as below--it is not public.

            "State": {
                "Code": "available"
            },

            "Tags": [],
            "Public": false

Now when I try to load it I got below error report:

~/aws-fpga$ sudo fpga-load-local-image -S 0 -H -I -F agfi-XXXXXXXXX
Error: (5) invalid-afi-id
The agfi id passed is invalid or you do not have permission to load the AFI.

However, if not using -F flag, I can load it correctly:

~/aws-fpga$ sudo fpga-load-local-image -S 0 -H -I agfi-XXXXXXXXX
Type  FpgaImageSlot  FpgaImageId             StatusName    StatusCode   ErrorName    ErrorCode   ShVersion
AFI          0       agfi-XXXXXXXXX            loaded            0        ok               0       0x04261818
Type  FpgaImageSlot  VendorId    DeviceId    DBDF
AFIDEVICE    0       0x1d0f      0xf000      0000:00:1d.0

why does that happen? I checked the fpga-load-local-image -F means

-F, --force-shell-reload
          Reload the FPGA shell on AFI load, even if the next AFI
          doesn't require it.

Will that "-F" flag really matter?
If not using -F flag, shell (which by my understanding is PCIE driver, interface stuff) shall always in FPGA? this should be fine