CNY vs HKD has an anomaly today.

HKD vs CNY

CNY vs HKD

The charts above show some anomaly which denotes an intervention in the FX market for HKD/CNY.  Maybe the China Central Bank is trying to remove the arbitrage opportunity by manipulating the currency.

http://sg-stock.blogspot.com/2019/03/hong-kong-dollar-has-been-depreciating.html