The source resolution is 3840×2160@60Hz (4:2:0).

When using fast switching, the output will become 3840×2160@30Hz (4:4:4).

Is it the scaler mechanism that causes the output to become 3840×2160@30Hz (4:4:4)

If so, is it possible scaling to  3840×2160@60Hz(4:4:4) ?

VE8950R output resolution can up to 4K2K@30Hz(4:4:4), it does not support 4K2K@60Hz(4:4:4), but the input source can be a 4K2K@60Hz 4:2:0 content. 

Although we can input 4K@60Hz (4:2:0) or 4K@30Hz(4:4:4) to the transmitter, but the receiver output up to 4K@30Hz (4:4:4) only.