I have a GA account, where someone added "WhatsApp" to the Default Channel Grouping like so:
Looking at the Acquisition > Channels report using source / medium as a secondary dimension and filterd by "WhatsApp", I noticed that WhatsApp is already covered by the standard channel Social.
Is GA unable to assign a session to two or more channels at the same time? It seems to me like all regular sessions started via links shared in whatsapp are recorded under the social channel, wheras only defective referrals are assigned to the actual WhatsApp channel.
The source/medium dimensions shows that all sessions assigned to the WhatsApp channel have the medium (not set). Any ideas where that sessions come from? It looks like spam bot traffic, which sets utm_source = WhatsApp while leaving utm_medium blank.
Note: The account was not set up by me and there is no documentation of what's been done.