I’ve been a member of a critique group for several years, and critiqued several novels and couple of hundred short stories in that time. Out of those, about a dozen have been close enough to stories I have at first draft stage or on my list of stories to write that I’ve felt I needed to add ‘BTW, I have a story similar to this that I may finish one day’ at the end of my critique so the writer didn’t come back in a few years to say ‘Hey! You critiqued my story and then wrote your own version of it! You [illegitimate person]!’
It happens all the time. I also remember an article by a Hollywood script reader saying that, one week, they read two scripts set on alligator farms. Never seen one before, never seen one since, but somehow the two they did see arrived at almost the same time.