The cuboid can be found in front of the ankle. When seated reach down to the front of the ankle and you should find a little hollow space between the ankle and the cuboid where there is soft tissue of about an inch long. If that is the source of your pain then we have the same problem.
Keeping your foot on the floor lift the arch slightly so your foot is resting mainly on the outside edge. Your fingers will feel that hollow space open out. What causes the pain is that hollow space collapsing inwards when you run gripping the soft tissue and small ligaments.
The solution offered to me was orthotics to keep the arch raised while running. I have been running a long time and only occasionally have had this pain while training, thankfully never during an event. I never went for orthotics and just rested whenever affected. Possibly my gait has adjusted over the years to compensate.
FWIW I saw "cublion" "sir snot" and "I vanilla" as posters to KK's thread and the posts for the first two were missing when I tried to view and I vanilla was a rant about vegetables I think and made no sense to me.
I also thought it was the unpleasant Flob or his later incarnations as his posts all vanished about two weeks ago. DF3 (Mr Anonymous) was a more likeable character.
I assumed it was trolling as KK has mentioned some coward(s) were stalking her threads and posts. I thought KK had posted that she would be on a short holiday and would not post for a while.