Mail is always "Downloading Messages".
I've noticed that Apple Mail is always "Downloading Messages". This process will happen approximately every 10 minutes. This is usually about 250-270 messages. (screenshot) However, there are no duplicate or extra emails. Further, the number of emails being downloaded usually doesn't change (maybe by 1 or 2 later in the day).
I have 4 emails accounts in Mail, all of which are Gmail accounts. I have gone through each account settings and made sure they are all handled similarly and have the same options checked.
I believe I found the problem account, because I have tried to right-click and select "Take account offline" when I see that it starts to download messages. Once I take it offline, the downloading stops. I have tried deleting this suspected account and re-adding it, but it still does the same thing. Any help would be appreciated!!