I am playing Bedrock Edition Minecraft on my XBox One, pure survival mode (never cheated or broke the survival setting). I recently built my conduit on the bottom of the ocean, exactly to the specifications with three rings of prismarine block.  I know that I activated it since I now receive the underwater breathing and vision enhancement, anytime I am in the water around the conduit.  The problem is that I was not awarded the achievement for this.  To test if somehow I was not receiving achievements in general, I completed another achievement (9 maps completely explored and placed on a wall) and I was awarded the achievement.

I will be trying to break down the conduit again, and rebuild it again... but this is problematic.