I don't think the real bug here has been addressed or fixed. The exclamation point still shows, but when this all first started. I started not being able to interact with the settlement. I couldn't get the settlement to move around when I clicked and dragged. I couldn't collect on finished productions. When this showed up I'd have to log completely out of foe and log back in, making sure collecting the settlement was the very first thing I did when I logged in, otherwise I'd have the same problem again...and again.
Recently, I've noticed that when the settlement is frozen up like that, I can click on the parchment icon in the lower left corner of the settlement view (it lets you buy the next building in the development process). If I do that, the settlement view seems to blink, and wake up and start interacting with my touch pad.
This behavior is repeatable.
I use
Windows 10
chrome
HTML5