The speaker position is displayed in dependency of the incoming signal, so the view can only be determined when signal processing is taking place. Cubase has a specific option that is enabled by default. It ensures that no signal processing is performed when playback is stopped. This reduces the CPU load drastically, but it makes it impossible for a plug-in to determine signal-dependent views such as the speakers. So, they are shown in a default position. Have a look at my attached screenshot. It shows a Cubase internal configuration that disables the automatic stopping of audio processing called "Synchronize Plug-in Program Selection to Track Selection". When disabling this option (unchecking), the functionality works as usual again! So, this is a valid workaround.