Blender to Unreal - Finger animation not working with only deform bones exported

Hello, I’ve been stumped for the past couple of days with this problem. When I pose and keyframe my mesh and its fingers using Blender meta-rig and try to export it to Unreal with only deform bones selected, seemingly everything works fine.

Blender viewport:

But then, if you take a closer look, the fingers are not posed or animated at all. They return back to their rest pose.

Unreal viewport:


I am using the meta-rig ik bones to control finger rotation.