sway: Two-finger scrolling touchpad problems

I’m having some subtle two-finger scrolling issues with the touchpad on my laptop. First I had to reduce the default scroll factor to 0.5 because it would scroll too fast in graphical applications (browsers, editors etc.) although after reducing the scroll factor, scrolling in the terminal window is now quite slow and was better with the default scroll factor. The main issue however is that when scrolling, the touchpad seems to simulate arrow keys (jumps by a discrete distance even with slight finger movement) as opposed to scrolling continuously relative to the finger movement like I’m used to. Would this be a libinput issue or something to do with sway?

Sway version: sway version 1.0-beta.2-211-g5a0c4234 (Jan 17 2019, branch ‘master’)

Linux distribution: Arch Linux

Touchpad: Dell XPS 15 9570 Synaptics Touchpad

Configuration:

input "1739:31251:SYNA2393:00_06CB:7A13_Touchpad" {
    scroll_factor 0.5
    dwt disabled
    tap enabled
    natural_scroll enabled
    middle_emulation enabled
    scroll_method two_finger
    accel_profile adaptive
    drag enabled
    tap_button_map lrm
}