That might mean the thread which retrieves file information was stuck on a particular file. It could be an issue triggered by a particular file or file type, and may (or may not) involve a shell extension something else has installed, depending on the file type.
If you run into the problem again, please make some process snapshots while the information isn't appearing and we will probably be able to see where the blockage is and either fix it (if it's something in Opus) or tell you which component is responsible (if it's something in a shell extension).