I noticed these roots on a UCD Sucrette cutting I started this year.  I did not change the level of the soil in this cup.  The roots were able to grow down into the soil without drying out.  Maybe the humid weather helped but it also has been in the high 90's at times in the greenhouse too.

The humidity probably helped a lot. Once the roots touched the soil they did not need any help.
This spring I had a bit high humidity in the rooting chamber and a number of cutting received from a specific location had many and long roots in the middle of the air and stayed so for weeks until I reduced the humidity and the roots in the air shriveled.

The more the merrier!

That is not uncommon. Any roots is good rrots/