How to stop smart object from trying to rasterise in photoshop and instead open in illustrator?

Anyone help with this please, I have a logo (illustrator .eps file) which I dragged into a photoshop document it duly places it as a smart object - great.

problem occurs when I want to edit said object in illustrator (which I'm pretty sure has been working fine for years by double clicking the smart object layer icon and then it opens illustrator to edit the file) double click now makes the smart object try and rasterise itself by opening it with photoshop, am I going mad here? is this the normal behaviour and I've just never noticed it before or has something fundamental changed during an update that I was unaware of until I've come to use the feature.

Thanks in advance.