That makes a lot of sense! I've also noticed I stopped getting the exclamation mark, and I also don't think I'm getting new emails any more.
On another note, I came to post a bug I found on the 2-player map. I used a Ballooner to found a settlement in the interior of an island, but because there are no nearby water tiles, I cannot build a new ship to leave!
Here is an image describing the problem: