How to prevent the development of insight to become ignorance anew? It is necessary to develop insight in the way ignorance lies at the basis for the conditioning of suffering. See 12 links of dependent co-origination. Insight in the conditioning of suffering is developed by seeing the four noble truths at work at every aspect of the dependent co-origination. Ie: fabrications are suffering because these will "colour" experience, therefore ending the fabrications (unskilful actions, complex emotions, fixed ideas,etc...) is to be achieved by developing wisdom instead of ignorance, and finally this transforming of ignorance into wisdom becomes the path of transformation. When then does the newly acquired skill itself become redundant and a hindrance to liberation?

------------- EDIT--------------

Somehow the thinking part, the studying element of the development of wisdom creates a structure essential to gain insight into suffering. This knowledge may then become a kind of established truth, again giving rise to clinging to it, craving for it, ... and ultimately the birth of "the truth". This doctrine now needs to be defended, is liable to decay and misinterpretation, ... in short suffering. As it is impossible to use the insight to overcome itself (this is like a vicious circle), the only option left is to know when to abandon the knowledge (like in the raft simile) lest it becomes anew a cause for suffering. I hope this does clarify the issue somewhat.
Well, Buddhism is not simply a doctrine or belief system that needs to be defended through clinging to its knowledge or the view. The wisdom mentioned here that is acquired through reading, thinking or studying has to be experienced through Vipassana meditation. Unless it is experienced through this way, this knowledge will become just another view among many other views in this world subject to decay and misinterpretations.
There's a seven step purification process in Vipassana where you begin simply from practicing virtue, give up all the wrong views midway and finally end in wisdom.
You go through the entire process similar to using seven relay chariots until you arrive at the destination where each chariot is used only to achieve its designated purpose and then you abandon it without clinging to it; this is explained nicely in Ratha-vinitha sutta.

&quot;... purity in terms of virtue is simply for
the sake of purity in terms of mind. Purity in terms of mind is simply
for the sake of purity in terms of view. Purity in terms of view is
simply for the sake of purity in terms of the overcoming of
perplexity. Purity in terms of the overcoming of perplexity is simply
for the sake of purity in terms of knowledge &amp; vision of what is &amp; is
not the path. Purity in terms of knowledge &amp; vision of what is &amp; is
not the path is simply for the sake of purity in terms of knowledge &amp;
vision of the way. Purity in terms of knowledge &amp; vision of the way is
simply for the sake of purity in terms of knowledge &amp; vision. Purity
in terms of knowledge &amp; vision is simply for the sake of total
Unbinding through lack of clinging. And it's for the sake of total
Unbinding through lack of clinging that the holy life is lived under
the Blessed One.&quot;
Ratha-vinita Sutta [Thanissaro Bhikkhu]

If the steps are followed properly, then it doesn't become a vicious cycle.