Isn't that all against the idea of a self-organized team?
Yes and no.
Since the 'team leader' is a member of the Team, his opinion should be taken into account. If any team member's opinion is ignored during organization, then that's a strong smell that there's something wrong with the whole 'self-organizing' situation.
One thing you and he need to take into consideration, however, is that Scrum recognizes no 'team lead' role. The only roles in the Scrum Team are Product Owner, Development Team Member, and Scrum Master. No member of the Development Team intrinsically has more decision-making authority than any other member.
The 'team lead' does not own the issue. However, neither does the person working on it. The entire Team owns each issue (once they've entered into the Sprint), and as such any complications or concerns regarding implementation details of those issues are the purview of the entire Team.
When something like this comes up, the details need to be discussed (note: not during the daily Scrum, that's not the purpose of that meeting) and a consensus needs to be reached. If the 'team lead' believes there is a problem with how someone else is approaching an issue, then what he should be doing is explaining the problem and convincing everyone that his approach will be better - not simply dictating how it should be done and assuming his orders will be followed. Likewise, this can and should be done when any Team member sees a problem with an issue being worked on by any other Team member. It's not just the 'team lead' who should do this.