TL;TD will be fixed in the next update.
It’s tricky to check if a VST2 plugin with two channels should be treated as two mono inputs (one main input and one side chain input) or if it’s plain stereo, in order to support side-chain inputs for VST. Seems that our tests didn’t do the job for izotope plugins, so we’ll now treat plugins with 2 inputs as stereo in doubt to fix this.
All this shouldn’t be a problem with VST3 plugins, so the izotope VST3 plugins will work fine right now as well. I understand that this is not a good workaround for old songs though…