I've noticed iMessage on my iMac is sometimes slow to update. For example, I sent a message a few days ago then wondered why the person didn't reply, I looked at my phone 40 minutes later to find she replied a few minutes after I sent it. Another time I sent someone a message and didn't see a reply until I looked at my phone 15 minutes later. But... then there are times when I can have a texting conversation with someone and it will update without a problem. I haven't found a pattern for when it lags. Sometimes it does and sometimes it doesn't. I've noticed this happening over the last few weeks. It was fine before that. Has anyone else experienced this?