This link has my previous notes on the same subject.
Shri Sunder-ji of advaitin group, gives the link to a page, which has the late Kanchi Paramacharya referring to one such puzzle. Read the whole post (a from Kanchi forum), as well as Shri Sunder-ji's post on advaitin. Here is the dialog from Kanchi Forum site.
PeriyavaaL : Know that there are Guttu Shlokas in Bharatam (Mahabharata)?
Myself : These are Guttu Shlokas because they were composed to reduce the speed of PiLLaiyar's (Ganesha's) writing.
PeriyavaaL : There is a Guttu Shloka in Gita! You know?
Myself : Don't know.
PeriyavaaL : ' aj~nAnenanAvR^itaM j~nAnaM tena muhyanti jantavaH | j~nAnena tu tadaj~nAnaM yeSAM nAshitamAtmanaH || ' (5.15,16)
"Atma who is jnAnarUpam (in the form of knowledge) is veiled with ajnAnaM (ignorance). People are deluded because of that. If the ajnAnaM is destroyed by jnAnaM , Moksha will be attained."
Isn't this doctrine puzzling, confusing? How can ajnAnaM veil jnAnaM ? If it is veiled, how by that same jnAnaM will ajnAnaM be destroyed? -- is the confusion. Vinayaka blinks. In those few seconds Vyasa has readily composed the shloka s of many chapters.
For this puzzle that comes in the fifth chapter, he gives the answer in the tenth chapter!
teshAmenukampArtham ahamaj~nAnajaM tamaH |
nAshayAmi AtmabhAvastaH j~nAnadIpena bhasvatA ||
To show mercy on the bhaktA s who always sing and think only about me and melt by those acts in their hearts, I as the jnAna rUpi (form of knowledge) enter the state of mind that remains akhaNdAkAram (not fragmentary, entire, whole) and is known as AtmabhAvam (state of the soul), reach the prati-bimbam (reflection), strengthen the jnAnam and set aside (the veil) of ignorance.
(In other words, svarUpa jnAnam by itself will not set aside ignorance. It only notifies its presence. But if the same svarUpa jnAnam is reflected by the
mano vRiddhi (expansion of mind)mano vRtti (a state of mind) [Correction thanks to the comment by Subbuji.] that results from continued experience of the state of meditation on the Vedanta Maha Vakhyas after studying and reflecting on them, that will immediately burn the ignorance. Even if the sun has the svabhAva (inherent nature) to burn cotton, it burns the cotton only when the rays touch it through a special lens!
In this way, PeriyavaaL has the capability to give answers for many Guttus.
sandarbhaH - occasion, circumstance, stringing/collecting together, arranging, mixture, union,
So, it seems that 5.15-5.16 is a puzzle that Vyasa composed to keep Ganesha busy thinking about the puzzle, while He himself could pause for thinking. The puzzle he answered in 10.11.