Do the contacts in question use WhatsApp? Also have you allowed WhatsApp permission to access your contacts?
Yes, the contacts in question use WhatsApp, and I have given WhatsApp permission to access my contacts.
Ok go to Settings > Cloud and Accounts > Accounts and make sure WhatsApp is in there and if it is click sync, and if it's not there add WhatsApp to your accounts.
Try this, go to Contacts > Then click the 3 little dots up in the top right hand corner > Mange Contacts > Sync Accounts and in there make sure that WhatsApp is there and switched on.
Im having the same contact problem. None of the above methods worked. WA only picks up 65 out of over 500 contacts. Also tried un- & reinstalling with no luck.
All pemissions are switched on.