I originally posted this in the ViX python 3 testers required thread but didn't get it working.
I have tested on ViX 5.5 and on OpenATV 7.0 and cannot generate a bouquet with ABM from a favourites.xml with a python 3 image.
All works fine on any python 2 image (ViX, ATV, Pli).
abm.log
favourites.xml
BBC One E Mid_20210726140358.jpg