[barrylanc]

Customer thinks I caused this. Do we know what it is?  The right one - zoom in.

[SB Cleaning]

Looks like a leaded door window to me....

[M & C Window Cleaning]

Looks like the right hand bevelled piece is coming unglued. I've seen this happen on a number of doors, usually after a number of years.  The glue that's used to stick it on is breaking down. WFP certainly wont cause it to happen after one clean, but over time it won't help it once it starts to break down. However, if it's exposed to the weather neither will rain.
Unfortunately, people often want to blame somebody when these things happen and we are often targeted rather than poor manufacturing or normal wear and tear. I've had it happen a few times over the years even when I was a trad window cleaner

[NWH]

The bottom section is starting to show signs of it as well manufacturing default.

[swanson]

Certainly Not your fault
Wear and tear

[jd services]

If your equipment or method caused it, all 4 would be damaged.  Customers are often looking to get household repairs done at contractors expense.

[NBwcs]

I think you need to apply a twattax to this customer next time your putting your prices up , enough to hopefully mean shes becomes someone elses nightmare custy.

[Arnold Palmer]

Nowt to do with me love.

[NWH]

Yeah you caused this with a soft brush I think not,some of the products around today are of poor quality. The lead on PVC windows these days don’t seem to last anywhere near as long as they once did.

[Richard iSparkle]

agreed with most on here.

WFP wouldn't cause this if its all working properly. if its designed to be open to the elements, it should be able to withstand water.

we had a similar thing with front doors. a few neighbours resin front doors on a new build estate were wearing badly with the top layer coming off . they all talked and worked out that it was due to the pure water.

even when i pointed out to them that about 70 % of the doors on the same estate, all-around their house, were wearing the same... and we didn't clean any of those... AND we cleaned another neighbour of theirs, with exactly the same type and colour of door... AND his wasn't showing the same signs...

EVEN then they KNEW it was caused by our pure water.

a very strange folk human beings

[NWH]

Very hot water would do that though if it was held over that particular area for too long.