Hey Nick,
you are 100% right! Checked the forum here, just to read what you guessed right and I just found out: Dynamo read the list longer than data was in the excel cells, so in the end the list cointained much null data…
I just don’t know why Dynamo does it like that, since I already copied the excel, edited the name of the excel, etc. …
Solution is to just clear the lists before handing it over to the main nodes: