Hi,
Version 8.0.0 comes with several styling breaking changes. Therefore the old MindSphere Theme is no longer working 100% correct, the same with the starter applications e.g. MindSphere Asset Pump example.
The MindSphere team is currently working to publish new versions in the Mendix App store which are fully compatible with the new styling behavior from V8.0.0.
Check the App Store on regular base, should come soon.