That's an important thing, I agree. Seen a few shocking gaps in my co-workers at previous jobs, and whenever time and energy allowed, I always tried to carefully (to not bruise egos) and positively[0] patch it with a quick mental model update. I don't fault people for being inexperienced, or for not growing up as a computer nerd like I did. I only start having issues if someone wasn't given knowledge they're supposed to by organized learning (hence my scepticism about bootcamps, but see jfarmer's comment in parrallel), or when they claim knowledge and competence they visibly lack.

Programming is a profession. As you say, learning on the job is normal and expected.

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[0] - https://www.xkcd.com/1053/