You will see this behavior on any of the Video IP cores (e.g. Scaler II, Color Space Converter, etc.) if you have any run-time control enabled but do not assert the Go bit in the Control Register.
The Go bit of all the Video IP cores is asserted by default if there is no run-time control enabled, or if they do not have a run time control option. However, if any run time control option is enabled, the Go bit for that core will be de-asserted by default.
To work around this problem, remember to assert the Go bit in the Control register if you have enabled any run time control for a Video IP core.
This is clarified in the Video IP User Guide version 2017.11.06.