I've been spending some time tweaking the Hiwattt profile from the exchange to come up with a Gilmour/Cornish-inspired rig that has stomps to get close to both P2 and G2 types of tones in one rig. To best explain the oddity I need to explain the signal chain first.
All of these stomps have been edited to my liking
Compressor
Muffin
Pure Boost
Fuzz DS
Also note that I've heavily modified the settings of the stock Hiwatt profile in the Stack section (Amp, EQ and Cab).
The plan was to leave the stomps 1 and 3 (compessor and boost) on all of the time and switch between stomp 2 to get a Cornish P2-type of sound and stomp 4 to get a Cornish G2-type of sound.
The oddity
There is an audible delay of approximately 2 seconds before the full effect of stomp 2 or 4 kicks in when moving from one to the other. To try it out do the following:
Activate Stomps 1, 3 and 4.
Turn off 4
Turn on 2 and listen closely... There is an immediate change in tone and then two seconds later the full effect of stomp 2 comes through????
If you simply turn off 2 again and then turn it back on... this delay doesn't happen when you turn it back on???
Now, turn off 2 again
Turn on four and listen even more closely and there is a very slight but audible delayed change again (although quiet a bit less noticeable but still there).
No idea???
I didn't perfect the rig but I just uploaded the rig under the working name that I was using for it Gilmour B=P2 D=G3 to see if anyone could test it to see if they could replicate what I've found.
Side notes for those interested in the rig itself - I used a G2 clone and a Dice Works Fuzz Epic to approximate the tones I wanted to capture. I use a Timeline for delay so I didn't concentrate too hard on whatever delay I have set up in there (and not active). David Gilmour or not hopefully you can appreciate - very versatile rig with fuzzy goodness. After a bunch of time tweaking to make it really versatile, the G2 setting rolls off to clean tones with the guitar volume really nicely. Something I hoped before buying the Kemper that it could do.