This happens also while using Ableton Live 10. To reproduce the problem, try this:
Don't select any instruments, view all of them then select the first one.
Use the right arrow to select the next. Once it's selected, select the next and continue. You should see a problem after a while.
The next selection is shadowed (the same as when you're moving the mouse over the next selection) to show that the next selection should switch and then it returns to the original before it.
I believe the same thing occured when using the knob to select the next and then pressing on the knob to select it but, I haven't tried this method except a few times.
When pressing the "next" button quickly and the next preset is not selected, sometimes you need to press it a second time. In some cases, you need to hold the button down until the selection is switched.
As mentioned before, it also occurs with Modular V3 so I doubt it's an issue with the synths unless they both use the same algorithms to read the midi codes.
My system is as follows.
Windows 7 64bit, 4gig memory, AL3 and Modular V 3 in stand alone mode. I have 9356 presets in AL3 and 865 presets in Modular V.
My drives are also 240gig SSDs so I can't see that the drives are slow or not enough memory.
The problem occurs whether or not I'm using the Bluetooth mouse or the USB mouse.
As mentioned before, I wasn't using the prev/next arrows to change presets so the problem wouldn't have been noticed before.
More specific info regarding the system are:
Mother Board: ASUSTeK COMPUTER INC. M5A97 R2.0 Rev 1.xx
Serial Number: 120700559500992
Bus Clock: 200 megahertz
BIOS: American Megatrends Inc. 0301 06/29/2012
CPU: 3.40 gigahertz AMD Phenom II X4 965
Drive: KINGSTON SUV400S37240G ATA Device [Hard drive] (240.05 GB)