[Defender] Defender Pro File Scan Stuck at 38.22%

Hi there!

Like the title says, the Defender Pro File Scan gets to 38.22% and then gets stuck there. I've cancelled and restarted a few times, and have even left it sitting for 2-3 hours. https://www.screencast.com/t/knTFYCRR5

Site is brand new and running on WP 5.0.2.
The only active plugins are 'Classic Editor', 'Defender Pro', 'SG (SiteGround) Optimizer', and 'WPMU DEV Dashboard'.
I'm using the Pro Theme from Themeco.

I've purged and disabled all cache through Siteground and increased the WP_MEMORY_LIMIT to 768M (max allowed for my hosting package).

The error noted in the debug.log is:
[02-Jan-2019 20:13:29 UTC] PHP Fatal error: Cannot declare class PHP_CodeSniffer_Exception, because the name is already in use in /home/niche420/public_html/wp-content/plugins/wp-defender/vendor/php_codesniffer/CodeSniffer/Exception.php on line 0


Any help is greatly appreciated!