Previous Sessions count seems to be off by one

The label above the mentoring area shows “X previous sessions” if you are mentoring someone you’ve mentored before. In my case, I’ve got 3 previous sessions, but the label shows “2 previous sessions”. If I click and open the modal, it shows all 3, but the label says " You have 2 previous discussions with …"

Not just 1, if I recall correctly. Sometimes it is wildly off.

Such as for this, only a portion of them are shown in the screenshot.