Currently, if IP Caching is enabled (EnableIPCaching) and an IP changes while the old one is still valid, Autosys isn't able to determine that it's invalid or no longer the correct host.
The manual method of updating the machine definition node_name only updates the Scheduler's machine cache and not the IP cache. Further action is needed to resolve this issue.
To clear the cache, a quick workaround is to turn Off the EnableIPCaching param, send a SIGHUP or pause/resume respectively to the UNIX/Linux daemon or Windows service, turn On the EnableIPCaching param and then send a SIGHUP or pause/resume respectively to the UNIX/Linux daemon or Windows service again. This allows all affected systems to be updated in one step.