2 days trying and given up with opacity mask..help please

Hi all.
I have tried for 2 whole days to get an opacity mask to show up.
Mask is 32 bit tga, and whether I choose rgba, or just a, or any combination of all channels, it will not show on the leaves in the screenshot. It shows on the sphere no problem at all. If I un-pin the opacity section, the base map shows up on the tree leaves, but doesn’t mask out, so it shows square leaves with the texture.
I use opacity masks all the time in studio max and vray, but Unreal is puzzling me.
It works in Unity faultlessly.

Any help would be greatly appreciated.
Cheers
Vertex Design

Fixed it myself…I disabled nanite on the leaves and it works perfectly.
2 days of hassle, and one tick to fix…aaarghhh
Sorry to trouble anyone.

Vertex Design