Duplicate order records causing countdown issues

Occasionally, a WooCommerce order will generate duplicate OTCE order records, as seen in the OTCE Attendees report. This is causing the available tickets to be understated, as some orders are being counted against capacity twice. We had to artificially inflate the Event Area capacity to compensate for this issue. Please advise.

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Environment

• Home URL: http://www.thewelldesmoines.com
• Site URL: http://www.thewelldesmoines.com
• WC Version: 2.5.5
• WP Version: 4.4.2
• WP Multisite Enabled: No
• Wev Server Info: Apache ++ HTTP/1.1
• PHP Version: 5.4.43
• MySQL Version: 5.5.42
• WP Acitve Plugins: 10
• WP Memory Limit: You have more than the required minimum memory of 64MB. Your current total is 256M.
• WP Debug Mode: No
• WP Language: en_US
• WP Max Upload Size: No
• WP Max Post Size: 50M
• PHP Max Execution Time: 30
• PHP Max Input Vars: 1000
• WP Uploads Writable: Uploads directory IS writable (/home2/thewely7/public_html/wp-content/uploads)
• Default Timezone: UTC

Software – Active Plugins:

• [ON]: Akismet by Automattic,
• [ON]: Custom Login Page Customizer by Hardeep Asrani,
• [ON]: Easy Forms for MailChimp by YIKES by YIKES,
• [ON]: Free & Simple Contact Form Plugin – PirateForms by Themeisle,
• [ON]: Jetpack by WordPress.com by Automattic,
• MailChimp Forms by MailMunch by MailMunch,
• MailChimp Forms by MailMunch by Mike Hansen,
• [ON]: OpenTickets Community Edition by Quadshot Software LLC,
• [ON]: Shortcode Widget by Gagan Deep Singh,
• [ON]: TablePress by Tobias Bäthge,
• Waitlists for WordPress by maymay,
• [ON]: WooCommerce by WooThemes,
• WordPress Countdown Timer by Jordan Calder,
• WP Maintenance Mode by Designmodo,
• YITH WooCommerce Waiting List by Yithemes,
• [ON]: Yoast SEO by Team Yoast

Software – Active Theme: Zerif Lite by ThemeIsle