Editing a service always leads to WARN message in the log file - Why?

[Marcel_R__Ackermann]

Hi. I am running JIRA 5.1.1. I just noticed that whenever I klick on an "Edit" action for a service (at secure/admin/ViewServices!default.jspa) then I end up with the following warning in the atlassian-jira.log file:

2012-08-14 17:33:48,224 http-<port>-4 WARN <my-user>1053x12639x1 r6lu62 <our-server-ip> /secure/admin/EditService!default.jspa [webwork.view.taglib.IteratorTag] Value is null! Returning an empty set.

The crazy thing is that this holds for *any* service, even the ones initialized on setup which I never touched before, and not only services I may have messed with.

Has anyone an explanation for this? Is this a bug/feature of JIRA 5.1.1?

[Marcel_R__Ackermann]

Addendum: This is the only log message I get, there does not seem to be any related messages in the log file. However, the message has been there for some time, the earliest message dates back to 2012-01-24.