Journalists at most news outlets do not choose which editor(s) they work with on a given story, except insofar as they choose to not quit their job. This does not feel like a fair basis on which to hold the journalist responsible for the headline chosen by their editor(s).
Insofar as a reporter works for an outlet that habitually writes misleading headlines, that does undermine the credibility of the reporter, but that's partly true because outlets that publish grossly misleading headlines tend to take other ethical shortcuts as well. But without that general trend or a broader assessment of an outlet's credibility, it's possible that an otherwise fair story would get a misleading headline through no fault of the reporter, and it would be incorrect to judge the reporter for that (as Eli says above).