Any stem deprived of light and remains moist will differentiate into roots.
Superficial roots are often caused by poor watering habits. Roots physically turn toward greater moisture in a mechanical way -- baked into how they grow. So, partial or superficial watering will cause roots to grow upward instead of downward.
1) fully saturate (+10% runoff, if soilless)
2) wait for healthy dryback and repeat.
if deviating, likely part of the problem.
i'd also prune off that lower growth resting on the medium. It wouldn't produce buds worthwhile anyway, so no loss.
could top off the medium a bit more, but if you watering practices are garbage, the roots won't drive downward as much as they should. Burying 'some' stem is fine.. .but if oyu bury too much or do it too often, eventually you may cause some rot in your stem in the time it takes to fully differentiate into 'root' due to its new context (dark+moist)...
To test what i mean, you could feasibly wrap any portion of stem with something that will remain moist or cna be re-moistened whiel also keep that stretch of stem dark, and within 1-2 weeks you'll have roots above ground. The plant has no CNS. It simply reacts in a local way to the environment. Bend a branch down and bury a portion -- the portion buried will eventually sprout roots.