Hi guys, we're hitting an assert in TimeManager::OnClockFinished in rare cases when stopping a storyboard.

The assert is in the following line:

            if (clocks.Empty())
            {
                // Clear any pending animation related with this target and dp
                RemovePendingAnimation(target, dp);

                // Clear animated property
                animatedProperties.Erase(propIt); <<<<<<<<<<<<<<< HERE
            }

(Line 813 in version 3.0.9). The issue is that propIt is no longer valid. The animatedProperties map is empty so something must have removed the properties in between line 784 when it finds the dependency property and line 813 when it tries to erase it.

I can change the line to this instead so it doesn't rely on the iterator remaining valid:

animatedProperties.Erase(dp);

Cheers,

-Steven