Although we got a "conditional accept" and the reviewers argued that we followed all suggestions of round 1 in a satisfying way, the editor decided to reject the paper. He argued with the journal's backlog.
Further, reviewer 2 had some new comments which she has not mentioned in her first review (and which did not raise because of our revision). The editor argued that manuscripts are rejected, if there are issues remaining after the first revision.
This was the worst experience I've ever had with a review process.