The manual says:
The symbols for clef, key, and
time signature are displayed at the beginning of each staff.
(Cubase_Pro_Score_12_Score_Layout_and_Printing_en.pdf — WebHelp Version)
In the given context “each staff” doesn’t refer to “each staff in a system”. It refers to “each system” (each system, regardless of the number of staves it contains). Thus, the time signature will not appear at the beginning of each staff (“system”).