Yup, that says it all on that link. Floor joist cross bracing - Specific Inspection Topics / Structural Inspections - InterNACHI®️ Forum
The bridging prevents rotation of the joist and helps distribute any concentrated floor loads to adjacent joists. While it may not have been a problem for 20 years, if the new owner puts a baby grand piano on that floor a problem could occur. So I agree with others you should mention the defect and move on.