Well spotted, thanks.

… why is there only half a heart there? …

https://www.peppercarrot.com/gd/viewer/misc__2010-07-21_Alic...

C is coeur (French).

The adjacent Jack of Clubs has only part of the trèfle icon.

Comparable:

https://en.wikipedia.org/wiki/French-suited_playing_cards#/m...