Ooh nice catch, that didn't jump out to me at first skimming. In addition to this issue you noted, the other more fundamental issue is that their "clinical outcomes" table is not stratified in any fashion.

So the results are meaningless, we know from previous studies that young makes are more likely to get vax myocarditis than covid myocarditis, so all this study effectively tells us is that younger people are better at healing than older people.