What turns clear liquid soap blue?
The color of the precipitate is strongly reminiscent of copper(II) hydroxide. I hypothesize:


Chloride corrosion of copper from exposed brass (ref 1 || ref 2)

a. Per ref 2 above, sulfate may also participate
Alkaline precipitation of $\ce{Cu(OH)2}$ in the neutrally-buffered soap
Insufficient $\ce{Na_4EDTA}$ to complex the amount of $\ce{Cu}$ corroded from the brass


It's also possible the blue material is $\ce{Ni(II)}$ complexed in such a way that its color is changed from the typical green-blue of $\ce{Ni(OH)2}$.