V70 – wiping water from -6 degrees no longer usable

Hello together The winter has arrived in the North German lowlands and the heater is really worth it now. The consumption is now about 8 liters, which is completely ok. Now the problem: the wiping water can no longer be used from about -6 degrees. The wiper arms move though (and from the headlights one hears the noise) – but nothing comes. Back as in front. Is this a safety feature, which is not in the onboard book? The water can not be frozen, the Beh older is almost full and there is also a lot of “winter clear” in it. As soon as the car is back in the garage for a few minutes and the temperature has risen – everything works wonderful. Do you have that too??? Thank you & Greeting Lars