When using the same attribute in multiple groups, it is strongly advised to use only one of these groups for the same product afterwards.
For example an attribute Resolution with terms like Full-HD or 4K could be part of a group Screen (like the resolution of a monitor), but also of another group Camera (like the resolution the camera is able to take pictures with). When both groups are used for a product like a mobile phone it is not possible to assign to this attribute different values for each of the two groups. This results in arbitrary and wrong rendering. This is a limitation in WordPress/WooCommerce.
To circumvent the issue this plugin has a feature to duplicate existing attributes. On the attributes page you will find the Duplicate action when hovering over an attribute name on the right-side table.