Hi, I tested again and TAD is the SPI generator (it shows in the lower left corner of the HUD) and when I slaved all to SPI, for example TGP, it points to the SPI (I see the diamond over SPI). It is the SPI (3-bar) as opposite to mini SPI (2-bar). Anyway I was searching for this topic in the forum and found this post:
https://forums.eagle.ru/showpost.php?p=1348142&postcount=30
"If TAD was SPI generator, and you hook the triangle, it will become SPI automatically because SPI generated by TAD is always the current active hook."
That's the key. TAD is the SPI generator and all you lock (hook) it becomes the SPI.
That's exactly what it is happening.