this still happens to me roughly once a week.
I made a thread about it when I missed 20+ messages in one day. and It still seems to revolve around when Aman messages. (which isnt often anymore as we mainly talk on BHB) but it still happens to random messages.
I've entertained the idea that it is because I am logged in on various devices (Wii U, Android phone, Kindle HDX, laptop, Desktop)