Drawing a quad using glOrtho work fine alone, and so does my shader-based quad, but together it's disaster

As the topic title says: drawing a quad using glOrtho work fine alone, and so does a shader-based quad, but together it's disaster.

Can you spot an error in my code / logic? Thank you so much for any advice that you might have.

The lines that are commented out start at line 581 in ssao.h:

https://github.com/sjhalayka/julia4d3/blob/8a3105d68b119f209195bf8e2900c80918cd70dc/ssao.h#L581