No open tasks, but Solution Overview shows open tasks

Hello,

we have a problem with the "Open Tasks" display. In Solution Overview for our QA systems are 14 open tasks displayed. When we click on the link and go to our Solution, none of our systems has open tasks, cause we re-initialized all QA systems.

But why are there 14 open tasks when all system belonging to this solution have no tasks active and configured? Refreshing in Solution Overview does not help.

Thanks for your help!

(Solution Manager 7 with SP-Stack 17)