I don't know where the author is from but this goes dead against common courtesy in the UK for sure, and probably similar places like Canada and Japan as well. In Japan you might expect the apology to be longer than the email content.
Thank you. I logged in to say almost exactly that. I was raised with very different cultural norms that are hard to remove. At times, I do come across as overly apologetic based on nothing more than, from my upbringing perspective, being polite.
No idea if I'm normal or not (based in the US, with a British family), but if I miss an email by a few days/weeks, I'll just say "sorry for the delay" and jump right into the actual content. And on the recipient side, I don't expect even that. If it was critical, I would have used Slack (or sent a follow-up email if it was something to an external party).