Hi there,
Thank you for contacting us with that question.
I have tried to reproduce your issue but in my case, everything is working correctly. Could you please reproduce your issue in JSFiddle? I need to see how you set the extremes in your chart.
In the meantime, please take a look at the demo that I've prepared for you, where
yAxis.extremes are set on the
chart.load event.
DEMO: https://jsfiddle.net/BlackLabel/ynog1f6m/
Waiting for your reply,
Best regards!