Yesterday this came to my attention. Sometimes reports are blank. Doesn't matter the module. These are OOB reports.I can go to Service request and just click down the line. Some will render, some do not.
I ran into this with a customer recently and we found in their infrastructure there was a separate reporting database that only replicated from Prod every few hours. This produced a situation where blank reports would show if the report pointed to an Incident or other such record that had not yet replicated from the Prod DB to the reporting DB.
I actually think this might have been a case with you, but I figured I should note something here in case you are a different Nick or others see this in the future.