The amount of current that flows from the positive to negative plate in a capacitor depends on the initial charge. So, if the positive polarity polarised capacitor C1 is charged to a voltage of 5 V and connected in series with a positive polarity polarised capacitor C2 that has not been charged, as visualized below:
ground ---)|---resistor---)|---ground
or
ground --C1 --resistor --C2--ground
The current flows from right to left. With the voltage drop across the resistor, there is a possibility that the potential between the resistor and C1 can go negative. So is this negative potential at the positive plate of C1 acceptable?