Audit datasource listed the users as unknown.
Check that the Audit data sent to CASB has the correct data fields.
In one case the timezone and user field was combined because the delimiting comma was missing.
Expected log format sample
source="%s{cip}", datetime="%s{time}", tz="%s{tz}", user="%s{login}", dst="%s{sip}", sent="%d{reqsize}", totalsize="%d{totalsize}", ua="%s{ua}", duration="%d{ctime}", url="%s{url}", referer="%s{referer}", action="%s{action}", proto="%s{proto}", rcvd="%d{respsize}", op="%s{reqmethod}"\n