Here are some photos!

Everything seems normal. The air bubbles around the stem are also normal. Same will happen if you stick straw or a chop stick in water. Air bubbles settle around surface irregularities. And it looks like you have roots forming too. They form out of nodes (where leaves where once attached). Makes it easier if you have a node or two under water. I say leave it alone for now and enjoy it.

The only you need to worry is if the stem/roots start rotting. If the underwater parts turn slimey to touch (you will see fluffy gel like deposits along the underwater stem) that would not be a good sign. You can add some hydrogen peroxide to the water to prevent fungal growth but pothos really don't need too much fussing to root in water. Try to keep the water on the warmer side to speed things along.

The plants will adapt better if you root them in soil (not water).

The advantage of water is A) you don't forget to water B) you can see progress.

While generally true, it depends on the plants. In my experience, at least pothos and maranta root very well in water and then adapt very well to transplanting into potting mix. In fact, bigger the water roots, the better they adapt to then being put in potting media. I generally have more success with propagation in water.