i tried new versions and the older ones from the 1.12.2 mod but all the blocks with camouflage are textured as stone. i tried different ways to place the block like with shift + right click or near a bock but it still did not change anything. the block sound is changed to the right block.

the stone in the picture is a secret chest

SecurityCraft does not have a secret chest. We have a password-protected chest, however that one cannot be disguised. Are you sure this bug report concerns SecurityCraft?

oh sorry, i wasted your time. it is part from an other mod, my brother told me that it was from this mod. so i think its best to close this.