The Bug:
The shaking animation as a result of freezing, does not show in first person.
Steps to Reproduce:
Stand inside of some powder snow.
Toggle your perspective twice. (Hit F5 twice).
Notice how you will shortly begin shaking as a result of freezing.
Switch into first person.
→ ❌ Notice how your hand/held item doesn't shake. (Freezing does not show in first person).
Relates to MC-164874, MC-25512 and MC-136841.