After the latest patch, Build 7608, finally the Custom Views do work again. Unfortunately we realized, that there is another issue:
When configuring a Request Custom View, it is only properly saved & functioning, when the ServiceDesk Plus language has been set to "English" (by the User)
However, the Custom Views do not work (get not applied) when created when the ServiceDesk Plus language is something else beside English (in our case it's German).
I'd really appreciate if this could be solved soon. Thanks.