This issue has two parts:
When a stand-alone web module is disabled, the value of the j2eeModSMState attribute in the j2eeModTable is still shown as running (4).
When a web module within an application is disabled, the j2eeModTable entry for the web module disappears altogether.
The workarounds are as follows:
Restart the clusters or server instances on which the stand-alone web module is deployed.