Thank you for your efforts, Flipp.
I already knew everything that you stated, but this doesn't give any explanation yet, imho. Troubleshooting is not an issue, I said it from the beginning.
I remember that someone I do respect here wrote some day that he didn't rely on [counter] and did it with vanilla objects. From this day I decided to apply the same rule to avoid [until] (I never felt sure to fully understand how it works with deep subpatches to be "driven" by the iteration)
My concern is that I'm shocked by what looks like a unpredictable behaviour of Pd.
This loop works from 0 to 100, but not from 0 to 200...