The problem is that Boeing have no idea of th3 root cause if the failure, and therefore no way of guaranteeing it won’t reoccur during the stresses of launch or exposure to space.
Their access is limited in that the valves are all mounted internally in the vehicle. Their available external testing if the valves shows no corrosion o4 material problems, they seem fine. They have been able to “jiggle” them using heat etc to work, but can they be sure they’ll continue to work?
They could roll the dive and launch, after all it’s unmanned, but would NASA feel safe to then go straight to manned flights without being 100% certain if th3 cause?
Bottom line - NASA won’t let them fly until they can identify the roof cause and prove it has been resolved. As such I can’t see how it can fly until they’ve been removed and had detailed internal inspections - however desperately Boeing argue the case with NASA.