Something is definitely different about Bok Jo’s leaves. Here in CT, they are noteworthy in that they are by far the largest jujube leaves. In fact, I made a post about it a couple years ago. Though I guess the question is are the leaves so big because it is happy growing here (stressed jujube often have smaller leaves), or is it productively happy because it makes big leaves to better capture the slightly less abundant light (vs the sunny SW).
A couple other jujubes also have noteworthy leaves- all my Honey Jar are wrinkled early in the season (easy to ID at a glance). Churchpoint seems to have small, but dark green leaves that stand out from other cultivars.