They should set roots wherever the stem is in the ground. You should be able to plant them a bit more deeply.

On account of squash vine borers, I've often gone around with a shovel, piling soil over segments of my squash vines. They vines then root, and have some "insurance," in case of attack.

George
Tahlequah, OK

I disagree squash will not root along the stem if you plant it deep, it might not die, but you won't get extra roots. And squash do not root anywhere the stem touches the ground they only root on the vine at the base of a leaf.

I wouldn't plant them deep.
I don't know where they make roots, but I know they make them.
It is common practice to "hill" squash. I have done it for at least 35 years and they do make roots, I just don't remember exactly what location along the vine or "crown" of the plant they are in.
I would never have a summer squash past July otherwise.

I have read some gardening book. it is said that squash, melons can be planted deep up to its seed leave. And tomatoes can be planted deep to its true leave. I grew winter squash before, I believe that the roots location is at the vine and leave joint.