The enchantment soul speed should only increase your FOV when you are standing on soul sand or soul soil.
However on the newest snapshot 24w18a it causes this visual effect whenever you jump no matter what you are standing on.
Steps to Reproduce:
1. Equip a pair of boots (Any kind) with soul speed (level 1-3)
2. Jump while standing still or when running
3. Observe
Linked issues
is duplicated by 12
MC-271420
Jumping Changes FOV
Resolved
MC-271437
enchantment bug fov
Resolved
MC-271492
FOV Switches Back And Forth On Elevation Change
Resolved
MC-271496
Soul Speed is triggered when player is not supported by solid block
Resolved
MC-271538
Wearing boots with Soul Speed to swim or jump the FOV effects is incorrect
Resolved
7 more links
slicedlime
Confirmed in 24w18a. Turn off FOV effects in accessibility settings to remove the jarring effect.