According to Aviation Weekly:
"Early estimates of the scope of the problem were overly conservative," Horowitz said. "Instead of threatening the health of the crew and damage to some vehicle hardware, the actual vibration levels generated as the solid-fuel first stage burns out can be handled with relatively straightforward mechanical fixes."
"You can mitigate this throughout the whole vehicle," Horowitz said. "You can do it on the top of the first stage. You can do it on the interstage. You can do it by the orientation of the tanks. When you get up to the CEV and service module, then you can put shock absorbers in the seats."