Athletic Bilbao have released a statement claiming midfielder Javi Martinez travelled to Bayern Munich without permission.
Martinez was shown on German television having a medical with the Bavarian giants and seemingly concluding one of the summer's long-running transfer sagas.
But the Basque club have now issued a statement on their official website stating that Martinez's trip to Germany was unauthorised.
It read: "Athletic Club would like to make clear that at no time did they authorise the trip their player Javier Martinez made to Munich on Aug. 28."
While Bayern are yet to make any comment on the matter, the Athletic statement added that the club are seeking an explanation from the 23-year-old Spain international.
Athletic are keen to keep both Martinez and forward Fernando Llorente, who has been heavily linked with a move to Juventus.
But the Bilbao side are currently bottom of La Liga having conceded nine goals in their opening two matches and things appear to be turning sour under Argentine coach Marcelo Bielsa.