When rendering songs that use sends, signal followers, and multiple groups I sometimes get volume differences.
For instance. A synth that suddenly has a much higher volume for a short amount of time before returning to the original volume.
Also when rendering groups seperatly:
Signal followers on muted groups/tracks do not do anything. I actually have to add a send to the muted groups that have signal followers on them. Set send on mute, mute the send track as well. Only then the signal follower send the information needed to the group/tracks I want to render.
I still would love to see a render groups function added. 
Also I’d love to see that signal followers on muted tracks still send their info.