6.5 minutes is soft boiled for a large (in US egg sizing) egg. Soft boiled eggs don't have fully set yolks or firm whites. These are the kinds of eggs you use for ramen.

If you want a fully set yolk you need more time (about 10 min or so), but that's a personal preference.

See: https://www.thekitchn.com/how-to-boil-eggs-perfectly-every-t...

If the eggs come from the fridge they need 13min for a fully cooked yoke. The key is to put the eggs in after the water is already boiling.

Are you sure your water was fully boiling? Not just little bubbles at the bottom of the pan, but the top is properly rumbling