Here is a small analysis on how pitch behaved unpredictably at Bangalore.
From day one there was a regular unpredictable bounce. Barring 76 balls i was able to record/update all deliveries. There were 522 balls bowled (minus 76) of which 332 were knee or below level. It is important that one look at their length as well. Shockingly in those 332 balls, 103 were either good length or shorter. Suggesting batsman were not sure about the bounce if they have to play off the back-foot or front foot. Out of the 40 wickets that fell, 29 were dismissed playing on the front foot.
Below graphic is snap shot of length bowled during 2nd Test match, and at what height it impacted the batsman when playing.
Here are the links to other posts of ongoing Border-Gavaskar series.