Hi,
This is the function of Open Swatch plugin, I will report to plugin provider to check this issue. Now we have a new generation of this plugin to fix this problem, it called “WooCommerce Variation Swatch“. You just need to deactivate the old plugin, you will see the message to install the new plugin. But you need to update your product attribute one again.
P/s: Our support forum is the best way to support, please keep in touch in this environment.