We have identified an issue running discoveries on Centos.
It appears the older shipping bash is incompatible with a variable substitiuon used and hence logging form the script to the application does not ossur.
This manifests itself in the GUI as the status (and other attributes) of a discovery not being updated.
Download the attached file and copy it to /usr/local/open-audit/other/discover_subnet.sh
Re-run a discovery showing the symptoms and you should see all is now fixed.
This will be included in the 3.1.2 release for Linux due shortly (along with the other errata for Centos and older PHP).
Apologies for the inconvienence caused.