Stereo Flanger issue oscillators

Hi everyone,
I am studying how to create a stereo flanger, after studying some theory i tried to copy the juce given code, then transposing the code to a stereo one.

I am having a lot of issues, first of all two pi/2 oscillators are needed so while initializing the oscillators i feed them with sin(x) and cos(x) (which is sin(x+pi/2)) functions. After doing so it looks like the osc have the same phase. How is it possible? I am even getting some strange (not clipping but popping) sound artifacts, I don’t know anymore where to look.


Here I created a public github repo to view the code, is anyone able to help?

Thanks in advance, have a nice day.