I have now replaced the old cable with another one. This would be the third tested cable. All good except for the 5th output mentioned above:
2. output 5 appears to be bad. See the gray rectangles (output 5 vs output 8). Checked the same setup for outputs 6 and 7 and it was the same outcome as for output 8. 5 stands out. 5 is the presumably dead output that has failed my previous test cable experiment.
If only I knew what part to replace…