Wavelab / VST setBusArrangements

There’s a particular workflow a client uses in Wavelab, where they create an empty project, add our plugin, then load an audio file.
This triggers this assertion in juce-VST3-Wrapper.cpp - 3267

    tresult PLUGIN_API setBusArrangements (Vst::SpeakerArrangement* inputs, Steinberg::int32 numIns,
                                           Vst::SpeakerArrangement* outputs, Steinberg::int32 numOuts) override
    {
        if (active)
        {
            // The host is misbehaving! The plugin must be deactivated before setting new arrangements.
            jassertfalse;

An error message appears in Wavelab, then it deactivates the plugin.

Is there anything we can do in our code to avoid this?