This has become a real frustrating issue for the last month on my Lumia 950: in more than 90% of cases, latest calls are not shown in call history. If i want to call back after a few minutes the same person who called me or I called, i have to use search for the contact, but the real problem is when somebody calls you from a number not saved in your contacts and you want to add it later, but you have nothing to add ....
Latelly, I got another strange issue: When my son is calling me, even his phone no. saved on three linked contacts in same format, the phone is not showing up any contact details - only the number as is it was not saved.