The slide friction multiplier seems to get rounded to 1/64 increments. The default is 3/64, taking either Fleetfoot or Burst Fire reduces it to 2/64, and taking both reduces it to 1/64. The intended logic seems to be -50% friction for Burst Fire and -25% for Fleetfoot.
The clip shows Burst Fire (left) vs Fleetfoot (right). The speed is the same until the slide "ends" and friction increases so it can round to different numbers.
The clip shows Burst Fire (left) vs Fleetfoot (right). The speed is the same until the slide "ends" and friction increases so it can round to different numbers.