Problem retrieving metadata

I have noticed a problem with a new rule.
All rules

Details of the rule

Results of preview

As you can see only one file (Office 365_1.pdf) is matched, the others get an error.
You can see their details here:

All rules

Details of the rule

Results of preview

As you can see only one file (Office 365_1.pdf) is matched, the others get an error.
You can see their details here:
