You could try the reporting the issue to the Dev mailing list…
[quote]
nagios-devel ([email protected])
This is a list for people with an interest in working on Nagios addons, event handlers, etc. It is also a place where you can report problems with the “core” code and suggest ideas for future enhancements. [/quote]
nagios.org/support/mailinglists.php
Also, the 3.1.x release train is, by all accounts “the first development/testing branch of the Nagios 3.x code” and “ODD minor versions of Nagios releases (e.g. 3.1.x, 3.3,x) will be considered experimental/testing” ( Nagios 3.1.0 Available ) so fingers crossed for v3.2.0 
HTH
/S