My research gives no definitive answers to your question.
My humble opinion is contained in previous threads previously mentioned, and of which you are most probably aware.
I maintain that all the major pyramids were most probably completed to the satisfaction of the builders. Once the Romans departed Egypt, strict state rule became defunct. With the advent of Islam, any monument was fair game for pilfering.
If you observe the current state of Bent Pyramid, it appears that the blocks were just too heavy and cumbersome for the Arabs to simply lever off, so they found weaknesses in the exterior of the structure and proceeded to break away the blocks from underneath.
I also maintain that a similar recycling operation was carried on at G1 and G2.
With G1, the removal of blocks was "simply" to lever them off from the top down as the construction technique appears to be one of just stacking the casing stones, one upon the other.
However, with G2, the construction technique is similar to Bent Pyramid in that the casing stones are an integral part of the edifice and their size and weight prohibits poorly equipped stone pilferers from large scale recycling.
Therefore, the same method of removal as in Bent was adopted. Weaknesses are evident in the remaining stone casing on G2.
However, at the level in the above image it is evident that the work of stone removal became very dangerous, as that corner, as well other parts of the exterior, became extremely unstable which necessitated the abandonment of the project.
As can be seen, about five to six courses have been propped up to prevent a large fail in the upper portion of the pyramid
The following pic shows the props on the face. One is huge.
Good questions are : Who got it up there? How? And when?
As for the deeper scarping, those blocks may have been smaller in size than those lower down, and the Arabs found it easier to pilfer them. Maybe, they removed too many which caused the instability.