Door breaks when I use a 'replace block' proceedure

Hello hello!

I am trying to create a door that ages over time (much like copper does). I have made a procedure that works will all other blocks, including trapdoors, and that works just fine.
But when it comes for the door to change to the next stage, it just breaks - Destroys itself.

Does anybody have any ideas? I tried adding the door to the Minecraft 'doors' tag, but that didn't make any difference

link to a grab of my procedure if that helps - https://imgur.com/OArImjy

Thanks