We have run this plugin happily for around 9-12 months now.
However recently we have separated the site in to two. We exported some bookings and imported them in to the new booking site via mysql.
Bookings come in on the correct time, however on google calendar they are showing as -1 UTC.
I have checked and the calendar is set to UTC +1 as is the server, as are both websites?
Any ideas? This only happens with the older imported bookings not any bookings made a fresh now.