You're not alone. At this point I'm pretty sure the majority of reports that there are lots of people lying on résumés and also being able to convince people in

You're not alone. At this point I'm pretty sure the majority of reports that there are lots of people lying on résumés and also being able to convince people in conversation that they know how to write software but who can't actually do [basic programming task] or answer [basic programming trivia question] are just cases of interview-stress-induced stupidity in otherwise competent devs being taken for savvy and insanely competent (but not at programming) grifters who were trying to trick the interviewers. Because I don't believe such ultra-convincing liars are both common and trying for software jobs (fucking why? Go into sales!), in numbers significant enough to explain widespread reports of seeing them in the wild. I think it's the stress of not having any idea what you might be asked about over an unreasonably-wide field of topics, or how you will be judged on your answers, making people forget stuff or act dumber than they actually are, when asked to perform under such (unheard of in real work, "server's on fire at midnight" stress isn't even half as bad and certainly not as adversarial-feeling) conditions.