Scan Stops after Forking

We currently have 3 copies of our website. One in “QA”, one in “Staging”, and one “Production”. QA and Production work fine, however scanning will not run in Staging. When run in debug mode the following information is spit out:

[Mar 23 15:08:53:1490299733.376050:4:info] Scan process ended after forking.
[Mar 23 15:08:53:1490299733.168409:4:info] Starting cron with normal ajax at URL https://www.securitycoverage.com/wp-admin/admin-ajax.php?action=wordfence_doScan&isFork=0&cronKey=aef975c78be61faa7f4607
[Mar 23 15:08:53:1490299733.141354:4:info] Test result of scan start URL fetch: array ( ‘headers’ => Requests_Utility_CaseInsensitiveDictionary::__set_state(array( ‘data’ => array ( ‘date’ => ‘Thu, 23 Mar 2017 20:08:52 GMT’, ‘server’ => ‘Apache/2.4.10 (Debian)’, ‘set-cookie’ => ‘wfvt_3538312177=58d42b54b27d3; expires=Thu, 23-Mar-2017 20:38:52 GMT; Max-Age=1800; path=/; httponly’, ‘x-robots-tag’ => ‘noindex’, ‘x-content-type-options’ => ‘nosniff’, ‘expires’ => ‘Wed, 11 Jan 1984 05:00:00 GMT’, ‘cache-control’ => ‘no-cache, must-revalidate, max-age=0’, ‘x-frame-options’ => ‘SAMEORIGIN’, ‘content-length’ => ’12’, ‘content-type’ => ‘text/html; charset=UTF-8’, ), )), ‘body’ => ‘WFSCANTESTOK’, ‘response’ => array ( ‘code’ => 200, ‘message’ => ‘OK’, ), ‘cookies’ => array ( 0 => WP_Http_Cookie::__set_state(array( ‘name’ => ‘wfvt_3538312177’, ‘value’ => ’58d42b54b27d3′, ‘expires’ => 1490301532, ‘path
[Mar 23 15:08:52:1490299732.551059:4:info] getMaxExecutionTime() returning half ini value: 15
[Mar 23 15:08:52:1490299732.549333:4:info] Got max_execution_time value from ini: 30
[Mar 23 15:08:52:1490299732.547682:4:info] Got value from wf config maxExecutionTime:
[Mar 23 15:08:52:1490299732.544112:4:info] Entering start scan routine
[Mar 23 15:08:52:1490299732.537822:4:info] Ajax request received to start scan.

I have tried the following either on my own or with my NetAdmin:
changing the max execution time
limiting the scan to one item at a time to see if it hangs on a particular option
comparing php modules between environments
memcached is not running
tailed apache err logs on scan run attempts
ensured adequate permissions access to the .htaccess file
compared file sizes between environments
updated all plugins and wp core
uninstalled, completely removed, and reinstalled the wordfence plugin
compared database tables between environments
ensured the config files for WP are set to the correct environments

There are probably other things I tried but can’t remember. Please help, I think I’ve read/tried almost every article and suggestion I could find.