The problem is that in the US stock markets, the market is ONLY open from 9:30 am - 4pm with extended hours from 7 am - 9: 30am and 4 pm - 8pm. From 8pm - 7am the next day there is usually 0 trading data available since the market it closed. the result is charts that look like below. As you can see there is a big gap between 16:00 and 9:30 since the market is closed.
Other charting software acknowledges this fact and compresses the chart so that there is 0 gap. eg
How does syncfusion deal with 0 trading data between extended hours? This is a 1 min chart over 2 days, imagine a 1 minute chart over a week, there will be 4 gaps in the chart where 0 trading history exists.