Why does the Field Extraction stanza in props.conf not work?

Hi, Neither of field extraction stanzas in props.conf works. Weird, for example alternative stanza for sha1 in Splunk Web works correctly. This works in Splunk Web: sourcetype="XmlWinEventLog:Microsoft-Windows-Sysmon/Operational" | rex field=Hashes "SHA1=(?[a-fA-F0-9]{40})" This stanza in props.conf does not work EXTRACT-sha1 = SHA1=(?[a-fA-F0-9]{40}) in Hashes Why? Tomas