Hi Eric,
Thank you for your update.
We have checked your reported query with our previously provided sample and the Spreadsheet printing properly with gridlines & working fine in our end. For your convenience, we have prepared a video to demonstrate this and the same can be downloaded from the below link,
However, we would to know the below details.
1. Please share the details or code snippet if you did any CSS customization in Spreadsheet (sample level) since in the provided screenshot – Spreadsheet header is customized with blue background.
2. Also, we suspect that it might be occurred due to CSS override in sample level. So, please provide the details about the stylesheet references that are loaded in your page.
Could you please get back to us with the above information or share issue reproducible sample if possible, so that we can analyze based on that and provide a better solution? The information provided would be great help for us to proceed further.
Regards,
Silambarasan