It’s very rare for the park to shut down for two days like this and hearing this new info means that it’s likely a very serious accident.
Possible ways a guest could fall out (purely speculation):
1- The weight is not balanced correctly (could be on the guest switching seats after the ride starts) or ride operator not checking for proper load balance.
2- Water pressure too high/forceful
3- Defect with a section of the tube itself
Just my guess, but most importantly hope the person injured makes a full speedy recovery.
Also, if this new info is true, I’d expect CC to be closed for the rest of the season while a full investigation continues from the park, insurance provider, and legal teams.