That’s not weird at all:
The front faces of your text are huge n-gons (= polygons with more than 4 vertices) and - even worse - non-planar n-gons.
For any kind of rendering (e. g. your After Effects screenshot) polygons will get triangulated. This triangulation works rather flawlessly if polygons are triangles (Obviously!) or quads. But with n-gons this process can result in a horrible shading mess, because the renderer does not know how to split up those areas into triangles consistently. But not only rendering is affected, some viewport shading modes can also produce artefacts, as you see in your Sculpt mode screenshot (BTW: sculpting on top of that messy geometry may not be as funny as you think).
If you want to avoid that, you should remodel your text in clean, all-quad geometry.