Ran into similar issues a long time ago. Believe it was due to either the response was too large, a timeout happened while performing the operation, or one of the hosts did not have the permissions set correctly for the account being used to enumerate and the script didn’t know what to do. I have one pulling back >2300 hosts so I know 200 will work fine for you.
Management Extender\Plugins\VMware ESXi 1\plugin\vcenter-plugin-settings.txt file, change
VM_WAIT_TIME to something much larger (I think we used 300).
For the VCenter permissions, make sure your account has