0s and 0 bounces since upgrade to 1.8.2

Since our upgrade to 1.8.2 we have
0s average visit duration and 0 bounces
(while there are 192 visitors for a certain period)

This is also for older periods, where we did have proper numbers before the upgrade.

We have
PHP 5.3.3
MySQL 5.1.49
no APC

Do you notice that Visitors > Visitor Log is showing correct data or not ?

Log is good, frequency overview is good, visitors in real time is good, only Overwiew with Graph - Roport on the Dashboard displays wrong.

Visitors-Overview Page is right…

OK, I removed the widget from the dashboard, and added it again.
Now it works…

Strange cache or other hiccup somehow, somewhere