@ustk When a sliderpack is linked to an arpeggiator, HISE prevents you from changing the maximum value of the sliderpack in both the IDE and scripting. If you try to change any of the default properties, it will automatically set them back to the defaults.
Unable to change sliderpack props.gif
It seems like this may have been intentional in order to prevent the user from accidentally setting the arp values to something other than what they should be. However, it becomes an issue when the arp values themselves can cause bugs, like the issue @Alex-Paradis described above.