By using Magenta Stereo Compressor, added in Magenta version 4, in Audio Units format (AU) in CL (control link) mode or not, you will be able to see an anomalous signal behaviour, this behaviour is completely different than in other formats, as VST2 or AAX.
The reason of this weird behaviour is due audio steam for the Magenta Stereo Compressor envelope follower signal is processed in channels 3 and 4 which are normally used for side-chain signals, but our products in AU format (Audio Units) are wrapped version through JUCE version 3 framework which not support side-chain in AU (Audio Units) format, and whereby the control signal is discarded.
We are working to update our JUCE framework to a superior version which include Audio Units format side-chain and control signals through channels 3 and 4.
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