Diagonal Border Over-lapping Button

I’m having an issue frequently where I try to place a button in a section with a diagonal button above it and the border seems to render the button useless. I’m sure this is just a Z-index issue and I’m hoping for an easily repeatable solution that I can use across multiple sites where I’m having the issue. I’ve included a link as an example.

The button doesn’t lead anywhere but the hover effect is a scaling effect so it should get bigger when hovered over like the button further down the page. Also if I take off the overlay on the image the button works for some reason? But it seems like the diagonal border is blocking it.