We are seeing this error in our DR Tool backup log.
2019-06-11 20:30:35 ERROR [pool-2-thread-1] com.esri.arcgis.webgis.component.Portal - {"error":{"code":500,"details":null,"message":"Failed to export site. Export of the Portal repository failed.
\\arcgisportal\\content\\items\\0b2ddccc355247f09bdac514024e9244"}}
The Portal \Content\items folder is indeed missing this folder.
I manually created a folder with the referenced GUID and the Site Export succeeds.
Will we have a problem if we ever try to restore from this site export? Does it make sense that a single missing item folder would break the export?