(prop("On Hold Since") < now()) ? dateBetween(now(), prop("On Hold Since"), "days") : 0
(prop("On Hold Since") < now())
Checks to see if On Hold Since is before the current date.
? dateBetween(now(), prop("On Hold Since"), "days")
If it is, display the number of days between On Hold Since and the current date.
: 0
Otherwise display 0