In the vanilla game, chests as well as their trapped chests counterparts are retextured during Christmas. This works with the mod at default settings with the Enhanced Chests setting disabled. (normal chests on left, trapped chests on right)

Turning on the Enhanced Chests setting will not do anything to the normal chest's textures (single + double), but it will revert the textures of the trapped chest counterparts, even with the Christmas Chests setting enabled.

In these screenshots I am using a modpack, however I did test this again using only this mod and the fabric api, and the issue persisted.