Custom Data Fields? parameters persist in the session too long

1. Go to Administer CiviCRM
2. Go to Custom Data
3. View and Edit Custom Fields (any, but remember which one)
4. Edit Field (any, but remember which one)
5. Do something ?illegal? (like deleting the Weight)
6. Click Save

You should now get a screen with an error, like ?Weight is a required field?

7. Do not Save nor Cancel, just click the Custom Data tab again
8. View and Edit Custom Fields (any, but other than in 3.)
9. Edit Field (any, but other than in 4.)

You get dropped back to the previous?s field error (i.e., you land at Group from point 3., field from point 4. and the error from point 5.).