These issues are fixed in the Video Scaler v2.1 core, available in 12.1.
The Video Scaler v2.0 has the potential for internal block RAM collisions due to the restriction regarding READ_FIRST mode and asynchronous clocking, documented in the:
This issue might not be reported in simulation and could cause the core to fail in hardware. As such, the core should not be used for production at this time.
The Video Scaler v2.0 in 11.4 and 11.5 has the potential for memory initialization issues as documented in the following Xilinx Answers:
(Xilinx Answer 34659) Spartan-6 FPGA Block RAM - Output Register of BRAM does not Initialize Correctly After Initial Configuration
(Xilinx Answer 34712) Spartan-6 FPGA Block RAM Design Advisory - 9K Simple Dual Port (SDP) Block RAM Initialization Incorrect
Please see (Xilinx Answer 31958) for a detailed list of LogiCORE IP Video Scaler Release Notes and Known Issues.