This is inconsistent with all other heart textures under some affliction.
Survival heart appearences:
[media][media]
[media]
Hardcore heart appearences:
[media][media]
[media]
Mockup of what frozen hardcore hearts could look like, achieved through a resource pack:
[media]Related issues
relates to
Attachments
Comments

[media][media][media][media][media][media][media]

An example of what hardcore hearts could look like, as achieved through a resource pack:
[media]
Can confirm in 20w51a.
Can confirm in 21w03a.
Can confirm in 21w05a.
Can confirm in 21w05b.
Can confirm in 21w06a.