@Trubadurex My apology, 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, is that correct?
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?