The problem you’re having is not a bug, but an incompatibility with a theme.
You updated to WooCommerce 3+, but the theme doesn’t support WooCommerce 3+. The zoom plugin does some changes to the theme in order to prepare for adding the zoom. The plugin recognizes that you have WooCommerce 3+ and does the changes specific for that. Unfortunately the theme messes up with the changes.
You have the following options:
1. you can downgrade to WooCommerce 2+, as this is what your theme supports
2. you can change the theme to any of the thousands available and ready for WooCommerce 3+
3. you can hire a developer to help you with your issue.