Lag of minutes for poloniex API `returnChartData`? It seems that Poloniex takes up to 2-3 minutes (with quite a lot of variance) to compile the OHLC data (API method returnChartData) of a period that just ended. I've experimented with 30 minutes periods, so 2-3 minutes is up to 10% of a period, which is a lot! 

Could it be that I'm doing something wrong? I'm using this python-poloniex wrapper, and I'm after the OHLC prices of a few BTC pairs.
No, you are not doing nothing wrong. It's internal issue of Poloniex.
Every day I see that most of cryptocurrencies have missed candlesticks. And after up to 40 min are updated.
Even on charts you can see that