@keremhd: While I fully agree with your opinion about the privacy implications of the shopping lens towards Canonical and what data is being passed around to them, this is not what this bug is about.
This bug is about the fact that Shuttleworth's statement, "We are not telling Amazon what you are searching for. Your anonymity is preserved" is simply not true in the current shopping lens implementation.
What you describe ("data leaking to Canonical") is a conscious design decision made by Canonical. Shuttleworth acknowledges it as being the way it works ("we handle the query on your behalf", which is true).
tl;dr: what you are referring to is Canonical's intentional data gathering; what this bug is referring to is Amazon's unintentional data gathering. These are two separate issues.