Yes, that is part of the basic functionality of the mobiles phones since several years.
It is especially useful for mobile phones, as we don't always have the network (in subway, in old buildings with thick walls, in countryside/mountain). In those cases, you don't have a notification of missed call. But the guy could have left a message, something that can be important and you won't miss (job, flat...).
Your friends calling from mobile phone can leave you an SMS or reach you through some other service, but when a company wants to hire you calling from a landline phone (no sms!), and need to talk with you as soon as possible, you are thankful when the phone tells you they called and left a voicemail when going out of the subway !

Jolla didn't answer any of my message with details, except than "We'll check and update TJC if there's any ETA. Thanks for the ping". I hoped they would have answered when I found this patch with something more meaningful about why they cannot do it like this, or that they have added this to some future update. Anything.

I know that this is not the only bug in their list, but it is a part of the basic phone functionality (as in "Nokia 3310 had it"...) and a lot of people complained about it for missing messages and having to call it randomly to check (talk about "smart"...phone) so it is strange they don't react about this.

Jolla, if you read me, let me know how we can help on this ! You ask us to do it together, we are ready...

In the mean time, thanks to the help from the community (patch-manager, ideas and tips on IRC, tests on other operators...) at least we have something that works.