The docs for errgroup indicate that "the first call to return a non-nil error cancels the group; its error will be returned by Wait."
Since these are running concurrently, it's not predictable in which order the failure will occur. Sometimes it occurs right away, other times only after other goroutines have successfully run. On average, it sounds like 3-5 are running before the error. As soon as that error happens, the group is canceled and any goroutines that haven't yet been started won't run at all.
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