If I uncheck the Gridlines for Sheet in the View menu it works - on some sheets. I cannot figure out how to make them go away on other sheets. The Workbook is cloned from an Excel file, and the sheets that are able to use/not use the gridlines are those that were gridless in the original…
View → Gridlines is only for the default grid, so if your spreadsheet contains any borders, they will still show up. To delete those, Edit → Select All, then Format → Cells… → Borders and under Presets in Line Arrangement click on the Set No Borders icon and press OK.