According to Jmp manual the option By Column in the Search/Find window works like this

And indeed, if there are several cells with the same value, Jmp follows uses this rule to step through the matching cells and at the end it starts a new round from the top left:
But:
So, if you want to be sure to find a matching cell, please select the right column - or no cell at all.
(TS-00078231 )