Sprinting can briefly overcome slowness

The bug

When you begin sprinting, you very briefly seemingly ignore the effects of slowness. In some cases, this occurs every second or so while holding sprint.

How to reproduce

Method 1
1. Drink a turtle master potion with slowness VI
2. Look straight down
3. Hold sprint
→ You move pretty slowly
4. Start repeatedly tapping CTRL and W at the same time
→ You move in quick bursts, faster than you were moving before

Method 2
1. /effect @s slowness 20 50 true
2. Start sprinting
→ Every second or so, you move a little bit