Grade disappearing when I click render

hi all, using Davinci Studio 17.2 and every time I try to render a project the grade disappears on one clip and that clip only and I have no idea why? Before I click render the grade is there then when I click it the grade disappears on this one clip. I've tried the 'render in place' option on the edit page for that clip but it the file comes out corrupted with an error message. any help?

Nothing immediately comes to mind, so I want to check for Operator Error.

Have you completed any of the training manuals for Resolve yet?

https://www.blackmagicdesign.com/produc ... e/training