I don’t remember the rules of the lower league, but I think you’re supposed to output 1 line per turn there too (please check the Output section of the statement). If you output more than 1 line per turn, the extra lines are treated as output for the following turns, i.e. you are treated as if you have output something even before you read the inputs for the next turns. Hence the warning you see in the console.
Fix: Make sure you don’t output more than you are asked to.