Nilfisks are good machines from my experience. Do you have a proper lance pani k ? Also do you flush and empty the washer after use? I,m actually guilty of forgetting to do this but had no issues so far for 2 years .
If you can fill your mix with warm to hot water this may help , alongside cool panels in shaded areas if possible already wetted down .
also dont forget , if your car is often protection detailed i reckon the foam will 'fall away' that bit quicker. Just a theory mind.