In effect, you want to apply some validation rules within a grid edit report, but without the automation that would be available with rules on a form. In situations like this, I've often found it handy to create a formula-text field called "Warning" that's blank if all's well, and put the field on the grid edit report. This is especially handy if the grid-edit is within a form that's being edited. Here's how it might work in your example:
1. The "Warning" allows html and looks like this:
If( not ( [Material Cleared by Supply Chain] and [Schedule Denied by LPM] ), "",
"<span style='color:red; font-weight:bold;'>" &
"Warning: Re-review required. Uncheck 'Material Cleared by Supply Chain' " &
"</span>"
)
2. If the grid edit is within a form (i.e., it's a detail table on a master record that's being edited), then create a summary field on the master record that counts the number of detail records where "Warning" is not blank. And on the form, create a rule that aborts the save if the summary field is greater than 0. The rule aborting the save would have a message saying something like "Please correct the check-box for the Supply Chain."
Or, if you don't want to put a burden on your users to uncheck the box, but you have a master-detail relationship, you could create a Quick Base Action on the master table that says, in effect, when a record is modified and the number of warnings is greater than zero, edit the related detail records to uncheck all the boxes. While this frees your users from having to do the unchecking, it makes the system a bit less transparent, which may be a downside, depending on the sophistication of your users.