Bug in the plugin

I tried to create a custom tab which worked but it also created a tiny tab right at the beginning with no text on it. The only way I could get rid of it was to disable the plugin. I tried the plugin just with woocommerce enabled but it did the same again. Please could you take a look or let me know if I’m doing something wrong? Thank you.

https://www.ads-software.com/plugins/woocommerce-multiple-tabs/