Just read Earnest Bywater's blog where he's changing his latest story because some idiots are know it alls that think a 0.22 calibre short sub-sonic can't work in a semi-auto. To all of them, it's a damn story and so long as it doesn't impinge on the action, I'm one who'd not bother due to the entire thing being Fictional. In his case, I'd change all references to it being a BFG with a 60m Barrel that fires a 1g round of Antimatter that only generates enough energy to pop a ballon just to screw with them.
Seriously, the things to report are typos, italics and other formating errors when they occur and the biggest is wrong names being used. I've seen many stories where they start with "Hohn" and end up calling them "Sally" several times due to editing issues. Those are the kind of errors we need to know about. Now if they start off with reference to a 65 Mustang using a straight six to a V8 without an explanation, then I'll point it out as that's too jaring a change. Otherwise don't sweat the small stuff if it doesn't throw you out of the story. If it does, then get some help with the OCD or at least keep you complaint to yourself