This appears to be an artifact of two distinct problems:
 1) provision_AutoUpdate declares success, but verify immediately
    fails.  In some cases, the the failure indicates that
    the AU in provision failed silently(!).
 2) The parser that constructs a status message from status.log
    concatenates the two status messages, indicating a status
    that reads "failed, completed successfully".

There's a sample status.log here:
    https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/66249530-chromeos-test/chromeos4-row10-rack12-host2/

Here's the relevant content:
START	----	provision	timestamp=1465494274	localtime=Jun 09 10:44:34	
	START	provision_AutoUpdate	provision_AutoUpdate	timestamp=1465494274	localtime=Jun 09 10:44:34	
		[ ... ]
		GOOD	provision_AutoUpdate	provision_AutoUpdate	timestamp=1465494969	localtime=Jun 09 10:56:09	completed successfully
	END GOOD	provision_AutoUpdate	provision_AutoUpdate	timestamp=1465494969	localtime=Jun 09 10:56:09	
	[ ... ]
	FAIL	----	verify.good_au	timestamp=1465494971	localtime=Jun 09 10:56:11	Last AU on this DUT failed
	[ ... ]
END FAIL	----	provision	timestamp=1465494980	localtime=Jun 09 10:56:20	

Bulk closing Infra>Client>ChromeOS issues untouched in over a year.