OK. it works. I have now managed to talk to my API and pull back the JSON it needs and thats all fine. I may have got there in the end but moving the .platformio dir seems to have been the answer.
I could also change update the framework but I will leave as is for now.
My OP still stands the error message wasn’t helpful, I suppose now we think that the path was being truncated you could loosly argue its sort of correct but not in a way that points you to what needs fixed.