While ULA studies Vulcan booster anomaly, it's also investigating fairing issues

"The Vulcan payload fairing is built by the same supplier on both Atlas and Vulcan, and I would say there are substantial differences and substantial similarities between the Vulcan and the Atlas payload fairings, similarities in terms of the manufacturing processes in that they use a low pressure oven... and basically the same type of carbon fiber layup techniques," Horne said.

"Despite the booster nozzle failure, the Vulcan rocket's performance to overcome the problem convinced ULA and Space Force officials that there is no need for another test flight."

"Space Force officials hope to launch the first national security mission on Vulcan before the end of the year. ULA is already stacking the Vulcan rocket for this launch, although officials have not set a launch date..."

"Horne would not discuss the payload fairing debris observations in detail, he said the Space Force could elect to certify the Vulcan rocket for national security launches 'with open work as long as we're satisfied that we're on a good path to resolution' of any technical issues."

Read at Ars Technica