Unable to open chests with a half slab on top of it

So I made a storage system and there are half slabs on top of some chests and didn't have a problem before but now you can't open them you can use stairs and other blocks just fine but slabs nope can't use them 

https://drive.google.com/file/d/1l1qXFamWc6Fv7J6EaIQucoWiLxVQl1Uz/view?usp=drivesdk