sl value is glitched in the End

If you fly enough high in the End, the sl value in the debug screen is set to 15 but the rl value is set to 0
What I expected : The sl value was set to 0
What happened : The sl value is set to 15
How to reproduce

1. Go to the End with an end portal

2. Fly high

3. Press f3

I will attach a screenshot later