Jesus told his disciples to do as the Pharisees told them, but not to do what they did, because they failed to practice what they preached. So, does Jesus say that their “teachings” went astray or their behavior? It was their behavior.
Ah, you need to read a little further, my friend...Matthew 16:6-12.
Then Jesus said unto them, Take heed and beware of the leaven of the Pharisees and of the Sadducees.
And they reasoned among themselves, saying, It is because we have taken no bread.
Which when Jesus perceived, he said unto them, O ye of little faith, why reason ye among yourselves, because ye have brought no bread?
Do ye not yet understand, neither remember the five loaves of the five thousand, and how many baskets ye took up?
Neither the seven loaves of the four thousand, and how many baskets ye took up?
How is it that ye do not understand that I spake it not to you concerning bread, that ye should beware of the leaven of the Pharisees and of the Sadducees? Then understood they how that he bade them not beware of the leaven of bread, but of the doctrine of the Pharisees and of the Sadducees.
See also:John 9:39-41.
And Jesus said, For judgment I am come into this world, that they which see not might see; and that they which see might be made blind.
And some of the Pharisees which were with him heard these words and said unto him, Are we blind also? Jesus said unto them, If ye were blind, ye should have no sin: but now ye say, We see; therefore your sin remaineth.
Hardly a ringing endorsement, is it?