Hi Belle,
Greetings from Syncfusion.
Query: Frozen columns not working correctly
We have validated your query with the provided details and from your screenshot we suspect that you have used frozen columns feature with detail template feature. We would like to inform you that the frozen rows and columns feature is not compatible with all the features available in the Grid. The detail template feature is not compatible with frozen rows and columns feature. Find the below documentation for you reference.
Please let us know if you have any concerns.
Regards,
Rahul