It's been that way since Canada.
You'd think they bring an update in anticipation to align with the new technical directives that come into force for Spa... obviously might take some fine tuning before the optimise everything with it, but it shouldn't effect the bouncing too much. Have seen a bit of an improvement already from the last few Grand Prix, particularly from the SF-75.
New parts need to be tested and verified in P1 at least, I don't think it was ever a plan to only have one driver use new parts. Even Canada RW choice was a forced decision. Also, teams need all versions of all parts prepared for scrutineering, so fitting two different floors to two cars is the simplest way to do handle them across the pits.