No, I don't think that mucus is good.
I have a raff cutting in water after it wouldn't root in a complicated and over-dense Nep mix, and it has the scummy mucus stuff on the cut area. As far as I can tell, that's bacteria, but it seems to not be fatal to my cutting (so far).
Changing the water would reduce the bacteria problem temporarily, but I wouldn't suggest a water change; that water may contain hormones that the cutting released that may help it root. Again, it doesn't seem that the bacteria are harmful.
Also, you may want to try letting the rooting area get less light, but to keep giving the leaves light is important; they make the hormones and photosynthesize to help build thye roots. Browning of the rooting area is also normal.
Leaves open on cuttings even if they don't have roots sometimes. It's normal. But in your picture it looks like the growing tip is seriously browned. Now that is not normal, and not a good thing.
So, all I can suggest, based on my knowledge, is that you keep it how it is, and watch how it does.
Hope I helped,
Jimmy