Multiple unique values for the Transposed column are being used within the article groups.
Explanation:
Normally, the features of an article group are next to each other: in columns. If there are many features and displaying them in columns becomes confusing, it is possible to transpose: the features are then displayed below each other: in rows. This can be indicated in the transposed column when importing articles. However, this must be done in the same way for all articles within the article group.
Solution:
For the relevant article group, fill in the transposed column with the same value for all articles in that group.
