I’m having an issue with some waste pipework that I’ve never come across before! Customer has reported a leak on some 40mm waste pipe i installed under a kitchen sink about 18 months ago. It appears to have cracked but it’s like someone has taken a Stanley knife or a plastic pipe slice to it it’s that clean of a slice! There is a Quooker boiling tap installed which I thought could be the cause but customer assures me it’s only used for filling cups/ pots etc and isn’t actually ran into the bowl and down the waste. Any advice appreciated!