Having the exact same problem after upgrade to 188.8.131.52
According to this thread, the issue has been around since 184.108.40.206 (perhaps earlier?) www.magentocommerce.com/boards/viewthread/266685/#t361473
After upgrade from 220.127.116.11, the dashboard is missing months randomly from the YTD/2YTD overview, so while the overall sales figures/shipping totals appear correct, the visual indicator is completely inaccurate.
I know community ed. Magento is free, but why are releases labelled as \’Stable\’ when they\’re still buggy?
If anyone knows how to refresh/recompile the reporting graph to display months correctly, please post a solution. Would be most grateful.