I am not sure if this is a fact but I would like Blender users to pls try this:
Open a new start up Blender file, Set unit length to centimetres-metric. Add a uv sphere to the scene, add the wave modifier and press play on timeline. The wave modifier works fine.
Notice the sphere's dimensions is 2cm for x, y and z axis. If I increase the dimensions to say 2m each and apply rotation and scale, the wave modifier stops working.
If I resize it back to 2cm for all axis again, apply rotation and scale. the wave modifier works well again. Can I ask why this is?
The only way to apply scale and keep both dimensions and wave modifier animation is to use-apply scale to deltas. If I remember this should be similar to 3dsmax freeze transformations? I don't know why there is no tutorials about this in Blender about deltas or how to freeze transforms if a mesh is scaled or resized before exporting to ue4.