Hello Scott,
If may be a result of blurry images, as mentioned above, or cameras with high roll/pitch values (for example, camera that is looking nearly parallel to the ground). In such cases we recommend to disable cameras with big roll/pitch values (both negative and positive) prior to orthophoto generation.
Another reason is low face count values - huge polygons may cause the same effect, so please use larger face count value, in case it is 200000 by default.