Can't really show it cause my computer is refusing to printscreen it but while using shaders you can't see through the portals like it's supposed.

LIST OF MODS
LIST OF SHADERS TESTED
Sildur's Enhanced Default
Sildur's Vibrant Shaders (Lite, Medium and High)
SEUS (Low and Medium)
Chocapic's Enhanced Default
Chocapic's (Low, Medium and High)

Working as intended. Optifine's Shader implementation doesn't support rendering of multiple worlds (please direct any complaints at OF), hence BP disables its see-through portals when it detects that shaders are enabled.