I can't get tessellation working with Vulkan Desktop renderer

I am using ue4 4.21.2 and have enabled vulkan desktop sm 5.0 as the only renderer, as soon as all the shaders compile there is no tessellation at all.

The attached image shows that it should be supported and this was in 4.20 so im at a loss as to why it’s not working.

I have multiple materials (some paid for) that use different tessellation techniques and NONE show any displacement what soever.

Can anyone help?