It sounds like Boeing is doing a design enhancement. I found this article [1] that describes features for the bolts as:
> The fix also includes adding lanyards atop the door-plug bolts to “permanently secure the bolts to the plug” and “provide a visual indication”, says Crookshanks. “They’ll hang there and be visible to a mechanic that had taken the bolts out.”
> The fix also includes adding lanyards atop the door-plug bolts to “permanently secure the bolts to the plug” and “provide a visual indication”, says Crookshanks. “They’ll hang there and be visible to a mechanic that had taken the bolts out.”
[1] https://www.flightglobal.com/safety/details-emerge-about-boe...