The normalization peak should be a sharp injection and ejection of Normalization solution, with a plateau ideally in the same fluorescent count range as the highest measurement data. If the normalization peak injection or ejection is not precise the tube passivation could be uneven, air bubbles might interrupt the fluorescent solution, a pump could have stopped working, or the normalization solution could be too old. First, prepare a fresh normalization solution in RB1. Make sure you have added detergent to the running buffer. We recommend 0.01 % Pluronic, which is suitable for living cells. If that does not solve the issue, restart the device.