Thanks for your thoughts Louis!  I've thought it might somehow be chance, but the last thing I want is to lull myself into that complacency— I figure there must be something more going on. 

I can't recall any instance of fights or "drama" of any sort, or of missing major deadlines or any other big mistakes. I'm very tension-averse so I'm motivated to either amicably resolve an issue or let it slide if it isn't worth the trouble. 

Perhaps I should get in the habit of asking managers/colleagues for feedback before I find out I'm not getting renewed— maybe they'd be more willing then to share what mysterious issues I clearly must be having.

My question is: as a worker experiencing job churn, what’s the point when I should consider whether I ought to more deeply change my career path?

This job churn extends pre-Covid (though it has continued now as well). 

The issue is: I have several examples where a coworker of a similar background & skillset got a long-term position, while my contract wasn’t renewed  (the longest job was 2 years). I enjoyed my time at each of these places, and didn’t cause any issues from what I can tell. I seemed to do my work well. 

Since your best bet to improve yourself is hearing feedback, I’ve always politely asked “what I could improve upon” each time my supervisor told me I wouldn’t be renewed. Every time, their feedback has been vague. This has all felt quite odd, like I don’t know what I’m doing wrong— when I can point to clear accomplishments in my work.

These jobs ranged from policy analysis at the government, to journalist roles, to being a project coordinator at NPOs. 

Is there a point where I should go back to uni and study something with more job stability?