Diff seems not to work

I'm trying to produce diff between two revision of file but diff remains the same for any file revisions combinations. May be I'm doing something wrong?
Go to sources file pom.xml (https://bitbucket.org/atlassian/connector-commons/src/d2b72d22f627/com.atlassian.connector.commons/pom.xml)\\
Select revision you want and click diff.