Altiverb hosted inside vst~

Hi all - I've just discovered that the Altiverb reverb plugin, when hosted inside vst~, isn't behaving (Max 9.0.9 Sequoia 15.7.1). I'm finding it using [vstscan] and it shows up in listvst3 quite happily. It loads, but then won't accept any audio into it. The output is also silent, meaning it's not being routed through. I've tried loading the same in V8 of Max - Altiverb loads, runs and allows audio in and out, but [vstscan] is stating Altiverb is blacklisted even though it's working (doesn't say this in V9). Any clues??? Many thanks - Rob