@Trubadurex My bad, re-reading this now I realize that you never bounced anything, you just changed the level of your automation curve, and are using the same Sålstrenger#33 merged audio file in both case.
However, looking at your video closely I can see that in the second project the channel strip has a stereo input format whereas in the first it's a mono input format. At what time did this change and why? What is the format of the plug-ins in both projects?