Backface shading issue (Plane + Twosidedsign Node)

Hey guys,
I was wondering if anyone could assist me with this issue.
I have an animated book which turns pages on click. The pages are basically planes with morphs and bone.

I have an issue with the material of those pages (planes). I ticked the two-sided option, got 2 different base (diffuse) maps: one for front side - with a written text, second map just an empty paper texture.

I lerped the two textures and added twosidedsign into alpha of lerp and plugged them into diffuse. The other textures are normal and Roughness, AO and metallic packed.

My issue:
The front side of the turning page (plane) is okay. The backside - instead of having the empty paper texture has the entire text of the front page printed on it just whiter. I’m assuming it could be some kind of a lighting issue, but I’m not sure.

Any suggestions how to fix it?