It is common, and it is information rather than a verdict. The research finds that people whose interests fit their work perform somewhat better and are more likely to stay, with modest effects, and that the mismatch is usually about particular activities within a job rather than about the job as a whole.
What the evidence says
Nye, Su, Rounds and Drasgow (2012) meta-analysed sixty years of studies and found that vocational interests predict performance at work and in study, and persistence in both, and that the links were stronger when the fit between a person’s interests and their work was measured than when interest alone was. The effects were modest: fit tilts the odds, it does not decide them, and plenty of people do well at work they would not have chosen. Low, Yoon, Roberts and Rounds (2005) reviewed longitudinal studies and found interests stable from the early twenties through middle age, so a mismatch is unlikely to close by your interests drifting towards the job. What changes, when it changes, is the content of the work.
Where the mismatch usually is
Most jobs are a mix of types, which is why each type page on this site lists the other types it combines with. A primary school teacher’s day is social with a conventional strand of records and an artistic strand of display and performance; an accountant’s is conventional with an enterprising strand of clients and an investigative strand of working out why the figures disagree. Set your three letters against the activities of your week and the mismatch usually narrows to one strand: the artistic type with nowhere to go, or the social type in a job where people are colleagues rather than the purpose. That is more useful than a verdict on the job title, because strands can be present in jobs with very different names.
What a mismatch does not mean
It does not mean you are bad at your job. Interests are preferences, not abilities, and the interest test measures what you would choose, not what you can do. It does not mean you chose wrongly: people take jobs for pay, location, hours and chance, and a job can be a good choice on every one of those and still miss your top type. It does not mean the test is wrong, or that you are. And it does not mean the job must go; the research describes a tendency across many people, not a rule for one.
What it means for your results
Read your three types and the activities each describes, then notice which of them your week contains and which it does not. If your top type is absent, the finding is that the activity you would most choose is the one you have least of. If your top three are all present and the job still feels wrong, the interest test is not where the answer is.
The career interests test takes five minutes and shows all six types on strips. The career pages list what each type’s jobs involve, day to day.