> (As a personal anecdote, I've probably run into more concurrency-related heisenbugs in Go than I ever did in C, with C heisenbugs more commonly being memory mismanagement in single-threaded code with complex object lifetimes/ownership structures...)

Is that beyond just "concurrency is tricky and a language that makes it easier to add concurrency will make it easier to add sneaky bugs"? I've definitely run into that, but have never written concurrent C to compare the ease of heisenbug-writing.