bagbrother keeps spamming "You are not in a raid group" or You are not in a party. I notice this a lot when doing group finder stuff, dungeons/lfr. through a process of elimination of several addons I concluded its indeed bagbrother spamming this message.

Jaliborc/BagBrother#41

Getting the same error, after looking at the files it might be something related to the update detection code in updateDetection.lua? It seems these sorts of errors tend to be caused by chat messages, so could potentially be due to the code below (or may be from anything else that interacts with party members):

function Detection:Broadcast()
    for channel in pairs(self.Queued) do
        C_ChatInfo.SendAddonMessage(ADDON, Addon.Version, channel)
    end

    wipe(self.Queued)
end

To note, I seem to see these errors more often in instance groups, so it may instead be an error with using 'instance' instead of 'party' in SendAddonMessage()?