Start and end parameters in historical price data request are ignored

I trying to do some testing on historical coinbase data. Because I can only get 300 datapoints per request. Im looping the request and change the start and end paramter to got backwards.

My requests now look like this: https://api.pro.coinbase.com/products/BTC-EUR/candles?granularity=60&start=2018-11-09T17:11:08Z&end=2018-11-09T18:11:08Z

AFAIK they are ISO 8601 formatted and the time difference between start and end is correct.

However, im getting not 60 points but 350, so the end date is ignored and the start date also changes whenever I reload the link.

Can someone shine some light on how to correctly do the request for 1 hour of data?

The coinbase API docs say:

If data points are readily available, your response may contain as many as 300 candles and some of those candles may precede your declared start value.

So it looks like you need to parse and remove the extra data if you don't need it.