Difference in Voltage measurement


i came across a Probleme where the measurement of the voltage is off. As it should be 0 it shows -0.5V. but when i change the v/div or t/div it goes to 0V. And then if i apply a voltage it is different. Here also if i change the v-t/div the measurement it correct again. If i then take of the voltage its again at -0.5V.

Does anyone has a glue?
Its lib 3.53 and app 3.64.