mail app issues ios8

My iPhone 6 marks mail as read when it has not been read.
(meaning the blue dot next to the header disappears.)
But in only marks some mail as read, and some not.
I am using the Mail app, with IMAP configured.
Anyone know what this is?

Also, while it is configured to "push," my gmail app gets the messages minutes faster than the Mail app...

Thanks for any ideas you have.