When loading a plugin from the UXP Developer Tool (UDT), on macOS 10.0, 10.1, and 10.2 (Ventura) the plugin appears in the plugin menu with a check mark 
, however, the panel fails to load. It loads when selecting the plugin a second time. That is, to say, you must deselect and reselect the panel from menu to open it.
The Photoshop team confirms that this is a macOS bug. Cocoa does not properly show “auto-show” panels that are created while Photoshop is in the background. Apple is fixing this in a coming OS update.
The date of the fix and version number can’t be confirmed at the time of this writing.