which belts do you prefer

[RedArrow]

I think, if any signs of oil are visible on a regular basis anywhere *on* the surface of the timing belt itself, I suggest tracking the leak, the sooner the better. It is not good for the belt to get in contact with chemicals such as fuel, wax, coolant, oil etc. I hope you will find the leak and stop it.

Does your timing belt area still have the timing belt cover? Oil leaks from above (from the valve cover area) also can make their way into the belt area, by running down then through not-so-perfect sealing at the edges of the tb cover.

If you learned uploading some good pictures with your posts, we could also take a look and maybe help you to identify the problem. Taking a longer video is probably the best idea then it would be easy to share the link here after you uploaded your video on Y()utVbe.