the figure 1 is from PDF-SLVA289, a zero and a polar are included when a feedforward capacitor C1 is added across R1.For AC small signal mode,FB is shorted,R2 is not included in the loop,why the polar in the PDF-SLVA289 has R2?
the figure 2 is from TPS61081 DATASHEET which is an example of PDF-SLVA289,feedforward capacitor C3 is included