You need to exclude disabled  accounts or
rather include only active accounts through an LDAP filter on your
manage connections page for the profile  import. The filter you will
need to implement is (&(objectCategory=person)(objectClass=user)( !
(userAccountControl:1.2.840.113556.1.4.803:=2))).

Further, the magic 3 imports is FULL imports not incremental. You
will need to do 3 full imports to exclude people into the missing
from import. Further, you might need to clean your profile manually
the first time to get all of the old accounts out.

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