Experience orbs getting stuck in water streams.

I am trying to transport experience orbs to a collection point via water streams. This has worked in the past but now the experience orbs are getting stuck in the water. I find that I still level up at the collection point even though I am not near the experience orbs. When I go back to pick up the orbs, I do not gain any experience (because I already gained it). It still works to transport experience, but the actual orbs get stuck in water. (They do still travel up soul sand bubble columns, however).