פירוש על עבודה זרה 102:13

The problem with R. Oshaia’s statement is that it does not really explain the mishnah. The mishnah said that a coin, garment or vessel found near the idol are permitted. But surely these all can be decorative! The Talmud answers that these are permitted if they are not placed in a decorative fashion on or near the idol. But, by implication, if they were placed in a decorative fashion, they would be prohibited.
The need to limit the mishnah shows that R. Oshaia was probably not explaining the mishnah. The mishnah prohibits items that might have been offered to the idol and permits those that are not considered offerings. In contrast, R. Oshaia prohibits decorative items and permits non-decorative ones. It seems that the Talmudic editors used a statement with one concern to explain a statement that had a different concern.