Paper get rejected despite positive recommendations from both reviewers
This is a perfectly possible result.  The reviewers' recommendations are just that: recommendations.  The conference's scientific committee has the ultimate say over whether a paper is accepted, and they do not always follow reviewers' recommendations.

There may be quite legitimate reasons for a paper to be rejected despite positive reviews.  For example:


There might be an abundance of high quality submissions on the particular topic you submitted on (even if the deadline was extended because they didn't get enough submissions in other areas).
There still could be a scope issue.  Yes, a paper that is clearly out of scope should be rejected before it goes to review.  However, if the committee felt it was at the margins of acceptable scope, they might send it to review but ultimately reject it because the reviewers' comments weren't sufficient to overcome the scope problem.
The conference reviewers were generous.  It is hard to interpret the meaning of the reviewers' scores without seeing the distribution of all scores.  It is possible that the reviewers were really "nice" and scores tended to be high for everyone.  It is quite difficult for many people to give a negative decision when they know that someone else is going to see the result and be affected by it, so scores can tend toward the positive, and rejection recommendations may be rare. 
There was some kind of rule preventing them from accepting it (This should have led to rejection before review, but it could have been missed.  Of course, they also should have told you the reason if this were the case).


You are correct, however, that this is a fairly unusual decision.  I think you ought to follow up and ask for clarification.  It would be helpful for you to know the reason for rejection, and there is always the chance that there was some kind of clerical error, as well.