Citrix Virtual Apps and Desktops Machine Catalog displaying "Power State" as "Unknown"

Problem

You have a Citrix Virtual Apps and Desktops environment hosted with Citrix Cloud Connectors connecting to Citrix cloud and noticed that the management portal displays virtual machines in a machine catalog with the Power State as Unknown:

This appears to only affect machines hosted by a specific vCenter because virtual desktops hosted on a different vCenter displays the Power State properly. Monitoring the VDIs also indicate that users are not able to connect to them.

Solution

A quick search on the internet will only return the following Citrix KB that refers to an on-premise deployment without Citrix Cloud connectors:

VM's Power State Does Not Update And Shows As "Unknown" After vCenter Server Reboots
https://support.citrix.com/article/CTX238157

Although not stated in the KB, the issue can be resolved by turning off and turning On the Maintenance mode for the vCenter connection as such: