This is unusual. It should come back to your "fast" setting even though it may do so slowly, like a real Leslie. I tried this with all the presets and it works using another 3-button footswitch. Can you send me the preset you're working with to see if it works on my end? Just use H9 Control to export the .tide file and respond to this thread with it. Makes sure you're not assigning multiple functions to the same connectors – TIP, RING, & T+R.
Just as I suspected. You have "Increment Preset" and "Performance Switch" both assigned to TIP+RING. Only one function may be assigned to a switch at any given time.
Set parameter 1 – Foot Switch 1 (tip)
I see you have PERFORMANCE SWITCH and the "SET EXPRESSION PEDAL VALUE" mapped to your aux switch. Please understand the difference in functionality — one is a toggle function, the other is a momentary function and this could be a major source of confusion for the H9 since you're trying to map both to the FS3X.
PERFORMANCE SWITCH – In this case, it serves to toggle between SLOW/FAST
SET EXPRESSION PEDAL VALUE – allows you to instantly access the MAX value of a programmed expression pedal (or HotKnob) range. When you let go of it, it instantly goes back to the MIN value of that expression range.
I recommend watching this video to learn how to assign expression pedal (HotKnob) ranges:https://youtu.be/_gDiAys5L-4
Two ways we may instantly change parameter values on the H9 are using the HOTSWITCH and using an expression pedal. However, not all algorithms use a HOTSWITCH, as is the case with the Rotary algorithm you are using. Because of this, in Aux Switch Settings, we call it a PERFORMANCE SWITCH because depending on the algorithm you're either controlling a HOTSWITCH or a setting like SLOW/FAST or FLEX on some pitch-shifting algorithms.
On the algorithms that do use a HOTSWITCH, as is the case with all Space reverbs, you will not see blue ranges because this is not an expression pedal mapping. This is an instantaneous shift between values. [/quote]
This MIX and MAX settings for the HotKnob are the same as your expression pedal MIN and MAX settings. The YouTube link above explains it.
On the other hand, to program a HOTSWITCH, press the "HOTSWITCH" button down until the button flashes. Then, move the parameters to the values you want to shift to instantaneously. Press HOTSWITCH again to exit the programming mode. Now, every time you hit HOTSWITCH, you'll see the values immediately toggle from one value to the one you've programmed. The difference between this and an expression pedal, is that with a pedal, you may actually access in-between values on the way to the extremes, as delineated by the blue ranges.
If what you prefer is to instantaneously change values then I recommend using the HOTSWITCH. However, in the case where you have an algorithm like "Rotary" where the PERFORMANCE SWITCH is a "SLOW/FAST" control, the only way you'll be able to emulate HOTSWITCH behavior is setting your expression pedal ranges and programming one of your aux switches to control the "Set expression pedal value." Given you only have a 3-button aux switch, you're going to have to pick which three of the four options to control with the FS3X.
Increment, Decrement, Performance Switch, or Set Expression Value. You cannot control all four, only three and none can be mapped to the same aux switch. Only way around this is using MIDI.