My "Download Messages" statement is alway showing something like 40 of 60 messages. Never seems to download them all? Why? This has only happened since El C update.

Also, before this upgrade messages from the same source would list the in the left column and add them all on the right as one message. Example: My security system send pics when movement is detected. There would be one message on the left and all the pics would be under that one message on the right. Now I get a separate message for each one on the left making it harder to scroll through them. All this occurred after the El C upgrade. Any ideas on how to reset that?
Thanks in advance.
Todd
MacBook Pro with Retina display, iso 10.11