I take back what I said earlier. While the circumstances are different, this does sound like it may be related to the issues posted by others above. If so, a workaround would be to bind the values directly to components, rather than custom properties with component properties in turn bound to those custom properties. And upgrading to 7.9.13 (not available quite yet) or 8.0.x (see version 8 upgrade guide) may resolve it.