Empty staves displayed/hidden (unwanted)

I have a problem with empty staves (in 2 different scores):

• In the first case, one of the two Violin staves is not displayed, even if "empty staves" is set to visible.
• In the other case an opposite effect occurs (different score): A 100% empty stave is always visible, even if "empty staves" is set to unvisible.

In both cases this happens only inside one system (5 bars), the rest works fine.

Does anyone know how to solve that problem?