7.3 SPO and inactive transformation

Hi experts

We have built an SPO (DSO) and have also created a transformation between datasource and SPO:

For the DSO partitions the transformations from SPO infosource to the partition have become inactive after we changed the "primary" transformation between the datasource and the SPO:

We cannot activate this transformation either in SPO adminstration workbench neither separately under the partition objects.

Any ideas?

Thanks