This consciousness turns back; it doesn't go further than name-and-form

SN 12.65 says:

Bhikkhus, before my enlightenment, while I was still a bodhisatta....

Therefore, the teaching in SN 12.65 is Gotama's preliminary incomplete exploration of Dependent Origination. It is not yet complete Dhamma.

The words 'contact', 'six sense bases', 'mind-&-body' and 'consciousness' here do not have the same meaning as in the complete twelve condition formula because SN 12.65 only traces the real causes of suffering back to craving.

When the above words are used in the twelve condition formula, they have the following meaning, as shown in the case of 'contact':

contact with ignorance: avijjāsamphassajena

SN 22.81

But in SN 12.65, the words 'contact', 'six sense bases', 'mind-&-body' and 'consciousness' do not have the above meaning, namely, as 'tainted by ignorance'. The words are used meta-physically rather than in terms of suffering.

Gotama gets to feeling and asks: "From what does feeling arise?" He answers: "Sense contact" (rather than sense contact with ignorance). Then asks: "From what does contact arise?" and answers "sense bases". Then asks "From what does sense bases arise?" and answers "mind-body". Then asks: "From what does mind-body arise?" and answers "consciousness". For the mind-body to be known there must be consciousness. Then asks: "From what does consciousness arise?" and answers: "mind-body". Because for consciousness to exist, it comes from the mind-body (per SN 22.82; SN 22.56, etc).

Mind and body are the reason why the aggregate of consciousness is found.

Nāmarūpaṃ hetu, nāmarūpaṃ paccayo viññāṇakkhandhassa paññāpanāyā

SN 22.82

In other words, since a "visual form" cannot be known without sense organs, obviously the term "nama-rupa" does not mean the old Brahmanistic "naming-forms" because the sense organs must arise before a form can be experienced & named; as follows:

Dependent on eye & forms, eye-consciousness arises. The meeting of the three is contact. With contact as a requisite condition, there is feeling. What one feels, one perceives (labels/names in the mind). What one perceives, one thinks about.

MN 18

Note: In MN 18 above, the terms 'eye', 'forms' & 'eye-consciousness' are also used meta-physically rather than in terms of suffering. The terms are "neutral". MN 18 is similar to suttas such as MN 38 and MN 148, where sense contact is "neutral" (neither wholesome or unwholesome) and two paths can occur from sense contact, namely, the path to suffering or the path to nibbana.

The people who don't yet understand dhamma; who don't understand the difference between the different Dependent Origination formulas; won't be able to understand this answer.

In his analysis, Buddha sought to identify the semiotic precursor/counterpart for the experience of death. Going backwards from death, he identified the notion of "life" (jati, the notion of separate organism that gets born and dies) as the precursor/counterpart of death.

Going further backwards, he identified a chain of precursors/counterparts supporting each other in the process of semiotic development. These were appropriating experience aka becoming, object grasping aka goal-setting, obsession aka craving, associating a feeling with object, contact with object, six doors of contact, and namarupa or the labeled objects themselves.

He then tried to identify a precursor or counterpart for namarupa, information about objects and identities. He realized that vijnana or ability to differentiate objects from their background and from each other (the function that gives rise to our basic awareness of the world), is the precursor/counterpart of namarupa.

Naturally, the next step was to try and identify the precursor/counterpart for vijnana (recognition/differentiation). Upon much thinking, Buddha came to conclusion that namarupa itself was the counterpart of vijnana. Indeed, there may be no differentiation of objects without capacity for recognition, and there is no capacity for recognition without notions of objects.

At that moment Buddha realized that the entire chain of phenomena he has been analyzing, including death, is completely included in the realm of objective thinking. In other words, the entire experience of living and dying is a story our object-obsessed mind is telling itself. This realization was a huge breakthrough and a major step in the direction of Enlightenment.

At a later date, Buddha reconsidered this idea that vijnana and namarupa are each other's precursors and instead came up with an alternative chain which had "accumulated tendencies" (samskaras) and "ignorance" as two more links of the chain. This is the version of DO that ended up becoming the classic we know today.

Anyway, the importance of this realization still stands, that all our experienced phenomena are mind-made ("form is emptiness"), and this mind itself is a reflection of interaction of phenomena since beginningless times. In Mahayana we say, phenomena are empty, and mind is empty as well, these two emptinesses are a reflection of each other and yet they manifest as seeming reality ("emptiness is form"). This relationship is an important topic of analytical meditation in Tibetan Mahayana.