Williams made a big change in the design philosophy of their front wing in Hungary.
The team used to have their own, quite distinctive wing shape (inset), whereas the new design (main drawing) - seen on Bottas’ car only in Budapest - is based more on Mercedes’ philosophy. Note the new shape of endplate with the horizontal fin on the outside.
Another change is to the main plane and the stepped area on the outer lower edge of the wing (highlighted in yellow). This was introduced by Mercedes and copied by other teams.
As there was only one example available, Bottas got to use the new wing because he is ahead of team mate Massa in the drivers’ championship.