However in the final image there are also some tracts that are not terminated in the specified ROI (in this picture the tracts of both right and left hemisphere are shown which were calculated separately):
Alternatively, since you’re using ACT, and the regions appear to be defined based on cortical segmentation, you can use -seed_gmwmi. That will automatically enforce unidirectional seeding when from the cortex, and may well give more homogeneous seeding in this instance also.