I'm new to Studio One, and while playing around with the Console Shaper and realizing what a great feature it is, I also discovered a small limitation in its design. When using something like a high gain guitar amp emulation effect, the crosstalk and other processing from Console Shaper winds up getting fed into the amp effect, and gets amplified to a point where it's hard to manage. A gate helps a bit, or you can put all of the guitar tracks under a bus with a different instance of Console Shaper without the crosstalk, but then you're not really getting the full interaction of the higher-level Console Shaper across those tracks.
I briefly thought to myself, "Is this what they had to deal with back in the days when all songs were mixed on a real console?" But, then I realized that no, they didn't. In "real life" the guitar amp would be sitting outside the mixer with a mic, so the already amped signal is what would get fed into the mixer. They wouldn't put a guitar amp in a mixer insert (unless they were trying to do create a more unusual effect with it) so this issue wouldn't exist.
I have found several workarounds for this, but they are a bit awkward. The best one is probably to put each guitar track inside it's own individual bus, and put an instance of Console Shaper on each of those busses with all effects and passthrough turned off. So you then have the pre-mixer guitar amp FX chain on the actual audio track inside, but any mixer effects go on the bus. This allows the higher-level Console Shaper effects to properly affect the already amped signal each individual bus, but prevents it from passing through to the amp FX on each guitar track inside. This works fine, but it just feels somewhat weird to have each individual guitar track nested inside a bus. However, it's great that Studio One is flexible enough to allow this solution.
Another option is to put the guitar amp effects in the event FX bins. That also solves the problem, but is very inconvenient if you have a bunch of separate clips or comped takes on the same guitar track.
It seems to me that a more elegant solution to this problem would be to have a separate "pre-mixer FX" bin on each track (or one that is off by default, but can be enabled on any track that needs it). Any FX in this bin would be applied to the raw audio prior to entering the mix engine and would be unaffected by mix engine FX. The output from that bin would be then fed into the mixer chain that we have presently. As I said, I am new to Studio One, so maybe there are other ways of solving this that I haven't yet discovered, but I just wanted to offer the suggestion of a pre-mixer FX bin for some future version of S1.