Tackling and Heading skills refer to one another for Defenders

Tackling and Heading skills refer to one another for Defenders either in the database browser, or in the game.

Can someone tell me what is going on?

Here are some examples:

In the database browser, set Heading to at least 6 and Tackling to up to 2 and position to D, sort according to Tot.

Check these names in that search and in the game:

Stepan Grygorashchuk
Bence Varkonyi
Maytham Jabbar
Marco Lund
Djordje Skoko
Akos Kinyik
Lucas Mendes
Elliott Cotter
Edmond Curry
Edward Christian

In the database browser, set Tackling to at least 6 and Heading to up to 2 and position to D, sort according to Tot.

Check these names in that search and in the game:

Soumalia Magassouba
Nazariy Muravskyi