Estonia was not best buds with people's Garmins it would seem (see conor).
Nautical miles is hilarious.
Yeah I saw Conor was also having difficulties! It was working fine on Wednesday, it was just when I tried to sync it that it went weird. Its not just that its in Nautical miles - it also wont let me change the screens back to normal!! Is there a way to record your speed in knots on AP?
There could have been a software update with a bug for 610s.
I hear there are marshes in Estonia so that's probably where Garmin got the nautical idea from.