The reason was most likely because they justified their existence (and funding from the parent company) by saying there was a need to adapt the artwork to the t

The reason was most likely because they justified their existence (and funding from the parent company) by saying there was a need to adapt the artwork to the tastes of the local market. That may or may not have been true. The reality, however, was that a lot of the artists they contracted with had tight deadlines and were not well-informed about the games they were making cover art for.