[direct][/direct] unnecessarily displayed

That’s not a standard WordPress shortcode.

Do you have any idea as to which plugin uses those, or maybe they’re part of your theme’s features?

Its a feature of yithemes/cheope. Here is the link of shortcodes: https://docs.yithemes.com/cheope/#tab4

[tabs tab1=”Tab 1″ tab2=”Tab 2″ tab3=”Tab 3″]
[tab id=”tab1″]This is tab1[/tab]
[tab id=”tab2″]This is tab2[/tab]
[tab id=”tab3″]This is tab3[/tab]
[/tabs]

Ok, as that is a commercial theme, we ask that you please go to their official support channel. In order to be good stewards of the WordPress community, and encourage innovation and progress, we feel it’s important to direct people to those official locations.

https://support.yithemes.com/home

Forum volunteers are also not given access to commercial products, so they would not know why your commercial theme is not working properly. This is one other reason why volunteers forward you to the commercial product’s vendors. The vendors are responsible for supporting their commercial product.