In the JIRA Agile Rapid Board the systems shows an empty screen with a message:
'00000000000005.000' is an invalid number
This is currently a bug in JIRA Agile
Getting issue details...
which happens if the customer's locale do not use "." (dot) as decimal separator and use "," (comma) instead.
This has been resolved in JIRA Agile 5.9.7, upgrade using the Universal Plugin Manager to fix this.