Some objects "fail" to be imported

Hello, I am trying to import policy package from one Fortiagate devices and I note that some objects are not being imported and the below is an example of the import report:

"user peer",FAIL,"(name=user1, oid=2781, reason=This CA certificate is duplicated.)"
"firewall policy",FAIL,"(name=32, oid=3548, reason=This CA certificate is duplicated.)"

The first and second errors seem to be related to each other as the user "user1" is inlcuded in a group as source in firewall policy 32.

I cannot understand where is the problem in "CA certificate is duplicate"

The CA certificate seemed to be already imported when importing the configuration from another Fortigate device.

And also the below error appeared in the import report:

"user peer",FAIL,"(name=user2, oid=2782, reason=invalid value)"

here is the config of the "user2" as from the Fortigate:

config user peer
edit "user2"
set ca "G_CA_Cert_1"
set cn "user2"
next
end