Frame Generation on Egpu

I have an issue with Unreal engine where the frame Generation doesn’t work on a 4070ti run through an Egpu so a multi GPU system. I can recreate this 100%

The only way I can get it to work is by re-installing drivers. But on pc restart the frame gen stops working. This is only happening on Unreal Engine.

Frame Gen works fine on Witcher 3, Cyberpunk and A plagues tale

My specs are
i7-8750h
32GB Ram
4070ti Egpu
1070 laptop graphics - Gysnc so display is attached to this card

I feel it is something to do with the 1070 not being compatible with DLSS3 however it working fine on the 4070ti in all non Unreal engine titles