Sorry @trashy_incel, this was the first time I opened an issue and I was running crazy and did not found out exactly what was happening. It seamed that for some reason, something was being cached from test to test, even though everything was instantiated inside the function, so the submit test set was giving different results on some tests. Most likely something on my side, but running out of options, decided to open an issue. I'll remember to post more information next time, and to come back after completion (after getting all tests to pass, I stumbled upon timeout, so had to rethink on a faster solution)

The "Attempt" tests set are giving awkward results.
I tried copying one failing test to the "Test" set, and it gives the correct result there !
I tried copying the algorithm and the input to Python Tutor, and it also works correctly giving the correct result !
I have no idea why the attempt set is giving different results.

This is a reduced version of my solution, very nice !