Similar to MCPE-101969 but for sprinting with a speed boost. Sprinting requires affirmation from the server before the player actually begins to sprint, if the player has the Speed effect or a speed-like boost applied.

Steps to reproduce

1. Join a server or a Realm that has high latency/ping. Alternatively, set the randomtickspeed to 1000 on singleplayer.
2. /effect @s speed/build a beacon and set it to Speed (currently only tested with a beacon on Speed II), or obtain Soul Speed boots and place down Soul Soil/Soul Sand.
3. Sprint. (turn Dynamic FOV on for more visible results)

Expected behaviour

You sprint immediately on pressing the relevant buttons (sprint + forward, double tap forward etc.). If Dynamic FOV is enabled, the FOV increases immediately.

Actual behaviour

Sprinting only happens a short while after the keys are pressed. If Dynamic FOV is enabled, the FOV changes to as if the player had normal walking speed, followed by the correct FOV when the sprinting actually kicks in.

Notes

Might also be related to the now-invalidated MCPE-114068.