There is no development with respect to bid-ask spreads in EM currencies, for an example, USD/BRL, USD/ZAR and even USD/MXN. The spread of such EM pairs are widening. This indicates that liquidity is at a premium even for the most heavily traded EM currencies. 

From the above pairs, developments in the likes of USD/MXN give more cause for concern. It is used as a proxy for the broader EM universe due to its traditionally low transaction costs. In case of USD/ZAR, price action is instructive due to lack of liquidity and market making.