I am currently facing a weird issue in one of my customers tenant, they are deploying a large Yammer network, but they have realized that some users in the network are not able to modify the notifications settings.
After digging some time into the problem, we have notices that user does not have the mail option in the profile, so is it normal to not to be able to configure the notifications since this property is it not available.
So I decided to dig deeper, and I did some PowerShell into AAD and I was able to discover that his bunch of users that were not able to modify the notifications, they didn't have the mail AAD field informed.
I have done some reserch through documentation, and I have been able to find the following info:
Property in Azure ADProperty in Yammer
Email address Display Name Job Title Department Office Office phone Mobile phone Description
Email Display Name Job Title Department Location Work phone Mobile phone About Me