Screenshots of the results are basically useless without the seeing the timeline and the comp and some kind of description of how you are achieving your effects. If purging everything and rendering to an image sequence doesn't fix the problem then we need a lot more info. Where did the text come from? Is it all on one layer? Are these random frames or does the dot on the i in This have a missing stroke in every frame?
The buffer size and several functions are determined by the comp resolution, so by all means always preview your work at 100% size and zoom before rendering. Yes, Element 3D is that sensitive since it uses OpenGL. also check your bevel values. Broken up faces often means that the values are overcranked, resulting in self-intersections in non-convex polygons. and yeah, if you created the text from text layers, convert them to outlines and clean them up. Contours with many points spaced too closely can have the same effect. Fonts have different path requirements than normal shapes and therefore often have extra points in corners which only reveal themselves upon conversion.
This is all great advice! Thanks so much! I have never converted text to outlines, looks like I will go try that first and see if it helps. Any advice on how to do that correctly?