VST3PluginTestHost reports failed bus activation, old fixed Juce bug?

[KoenZyx]

I'm 99% sure this is the (fixed?) problem:
juce-framework/JUCE@0e85fec
"In the case that the host is using the same buffers for both inputs and outputs, copying an input to an output channel may end up overwriting another input channel, breaking the plugin's inputs."

I'm testing on windows10, using the Steinberg VST3PluginTestHost 3.3.10
I added the vst3 to the rack (probably not necessary) and then ran the unit tests, global and instance both give the same result.

and for the sake of completeness these are the settings in my txt file:

type instrument;
iolayout 0 2;
code kRbl;
midiin true;
midiout true;
playhead true;
taillength 8;
description Infos.txt;
compatibility 1.0.7;