Apparently, a number of Infiniti owners have this issue and have to get the retractor placed. This took some research on my part and I found another Infiniti website on a different car model descirbing similar problems. Most replaced the reatractor. Link is here:https://www.myg37.com/forums/g37-convertible/218832-seat-belt-retraction-fix-is-available.html
best of luck.