Thanks for a bug report. I believe it takes some time to google server to propagate this change from the Inbox to 'all folders'. What Evolution does: when you move to other folder, then it stores changes to the folder you are just leaving, and fetches changes for a folder you are just entering, more or less simultaneously.

I believe when you move from Google's Inbox to other than Google's [All mails] folder, wait till the changes from Inbox are saved, and then move to [All mails] folder, then you'll see they are properly marked as read. It works for me that way, at least.

Could you test this, please?

By the way, what is your exact evolution version?

Like I said in my first post, clicking the 'All Mail' folder usually fixes the problem. I'm running evolution 2.28.3.

To clarify: If there are unread messages, then the number of unread messages appears next to the folder and the folder's name is boldened. This is why I find Evolution's behavior annoying.

Thanks for the update. 2.28.3 is fine with respect of this. There is no connection between Inbox and [All Mails] folders in Evolution, there cannot be any, thus it's expected that the unread count doesn't change until the folder is refreshed, which does either on a refresh time, or when selecting/deselecting the folder. Plus that the changes are also saved on folder deselecting.

Feel free to reopen if I misunderstood the issue.