it's the guides
I've never used a 1/8" blade, only 1/4" wide, but the side guides can't touch the teeth or they will dull them. There's not much for them to run on with only 1/8" wide blades. Depending on the saw's guide system, you may be able to back them far enough away ... I donno? Roller bearings may not work in this case, you'll need cool blocks or oiled wood blocks.
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)