FabFilter

I occasionally use my Pro Q3 as a simple spectrum analyser- running my modular rig via an interface into AUM on an iPad. However, when I tried it today, Pro Q3- and every other Fabfilter AUv3 I own- was not displaying the spectrum analysis, despite the EQ appearing to function as it should. I also tried a standard desktop synth and a couple of AUv3 instruments, but the spectrum analyser was simply not working at all. Deleting and reinstalling the app had the effect of rendering Pro Q3 invisible when I tried to select it in AUM. Needless to say, there is no spectrum analysis when using any of the Pro (X) apps as standalone.

Am I missing something obvious? Or is there a bug affecting all Fabfilter AUv3s? I rather hope it’s the former…