Hi Andrew,
Greetings from Syncfusion.
We have created a simple blazor application based on the
provided screenshot using the latest version(v20.1.51). But, we are unable to
reproduce the reported scenario. By default, if height is not specified for
chart, then chart will be rendered in 450px. Kindly mention whether you have
specified height for chart. Please find the below sample link for your
reference.
Sample link: https://www.syncfusion.com/downloads/support/directtrac/general/ze/ChartSample-1212357820
Screenshot:

Please modify the above sample to reproduce the reported
scenario. It will be helpful for us to analyze further and assist you better.
Regards,
Swetha