Message from voicemail yet no missed call on iPhone 11?

I recently got an iPhone 11 and today I noticed I had a voicemail message stating I had one missed call. However, in my recent call list this number didn't show up. How is this possible?

This was during the day, my phone was not muted or in airplane mode, unknown callers are not silenced, there are no numbers in my blocked call list, and "do not disturb while driving" is off.

Any ideas? Thanks!

Edit: as mentioned in another comment by myself, reception is excellent here and I've never experienced a loss of signal. We've got a cellular antenna basically on our roof (figuratively speaking, of course).

Maybe the signal where you're located was low or inexistant, and the person just left a message.

Some companies from the US permit users to send voicemail to other users, without calling them. Also, some apps/services exist for that end.

https://www.techjunkie.com/call-directly-voicemail/

The same thing is possible in Canada, at least for Bell customers: (look at page 7) https://service.aliant.bell.ca/PS/pdf-download/3470874/default.pdf