Just because clinical symptoms of myocarditis resolve after 14 days does not mean the subjects in question will not suffer increased risk from cardiac scarring

Just because clinical symptoms of myocarditis resolve after 14 days does not mean the subjects in question will not suffer increased risk from cardiac scarring on an ongoing or even permanent basis. It would be extremely irresponsible for any scientist to conclude "they're totally fine after that point" and that is not what is implied by the paragraph you quoted.