Trim path works effectively on strokes and not fills. and even then - if you Ai object has anything but uniform width and basic brush stroke, when you convert it to a shape it will be converted to fill.
your options could be:
1. if possible modify you shape in Ai to be uniform width and basic brush stroke and reload your footage item
2. use other revealing methods such as the stroke effects, masking, etc.
When you are using trim paths on a fill you need to be aware of and properly set the first vertex if it is a path. The trim path will always be a straight line moving from the starting point to the ending point of any path or shape.
By animating the angle as well as the start and end point of a path you can successfully wipe on a rectangle or an ellipse by carefully animating the angle as the path is trimmed. Complex shapes that have curves or "U" shapes are much more difficult but they can still be done.
My normal procedure for using trim paths to reveal a complex field shape is to add an additional shape layer and a stroke through the middle of the complex shape. I make the stroke wide enough to cover the entire shape and then use trim paths on this layer to generate a wipe and then use the layer as a track matte for my complex shape.
When things really start to get funky I will sometimes create a gradient on a path in illustrator and then use that layer as the source for a gradient wipe.
It would be much easier to offer a solution if we could see more of your project then a tiny little section of a wipe that isn't working. It's pretty hard to diagnose a patient when the only thing you can see is the pinky toe on the right foot.