Same thing here, in Malaysia. It seems that when the exclamation sign appears, there is a wifi connection problem and your mobile data takes over. I have been logged in to my home wifi since last night, and didn't notice any connection issues. Then I noticed that my moto g had sucked up 21MB data even though connected to wifi. I turned off mobile data after that, but suffered no problems in connectivity. The exclamation mark still appears...
I've tried going through solutions on the net for hours but to no avail. Tried the setting up new user method, that didn't work. Only thing left is a factory reset, but I read another user's experience that it didn't work for him. So I'm reluctant to try, since it will be such a pain to have to back up all my data before the factory reset.
You said you have no issues with connectivity, but did lollipop sneakily put you on to your mobile data? You'd better check.
Ive seen some comments mentioning that the exclamation mark appears when the device is not able to connect to google servers. But I'm still able to access playstore. I'm really stumped, I'd leave it alone since I can still get a wifi connection despite the exclamation mark, but I really don't want to have to manually disable my mobile data every time I connect to wifi...
Anyone got anything?