Incompatibility / breaks website – Function get_cart was called incorrectly

Hello, our complete website is broken. We investigated the issue and found out, if we deactive the Ultimate Gift Cards for WooCommerce Plugin, the critical error is gone.
When the plugin is active it seems like the website is in some sort of “endless loop” and spams a huge amount of errors in the debug.log. The file becomes extremely large within seconds.

In the debug.log the error message is:
Function get_cart was called incorrectly. Get cart should not be called before the wp_loaded action….