Glenfarclas 1970-2008 Official for Germany

I've never had such a bourbon cask... Glenfarclas GLENFARCLAS 1970-2008 OB for GERMANY 46% Bourbon Casks The aroma has plum jam, dried fruits, grape juice, strong mint, a gentle barley sensation from the back, and upon drinking it has grape juice, mint, herbs, a rich and pleasant sweetness, a smooth tannic finish, and a rich, pleasant aftertaste. [Very Good] This is the Glenfarclas 1970 bottled in 2008 for official German market. It is noted as bourbon cask maturation. The aroma has a rich jam, dried fruits, and pleasant fruity notes like grape juice, with an impressive strong mint. When drinking it also has the same good fruity and mint notes as the aroma, with a well-balanced rich sweetness and appropriate tannic finish, resulting in a pleasant flavor throughout. The most mysterious thing is that it's labeled as bourbon cask maturation, but no matter how I drink it, it only feels like sherry cask maturation. By coincidence, I was able to compare it with the official 40-year-old Glenfarclas, and indeed there were quite a few different elements. However, the nuance of rich jam + grape juice + mint was a uniqueness I had only felt in sherry cask maturation before. Is this a mislabeling?