I believe the issue is with drain lines, either being too short or not connecting properly, which then allows water to spill out in unwanted ways...to the interior.
Has been a common Acadia/Outlook/Enclave thing, most of which dealers should actually be able to fix...but I've seen at least 2 Enclaves be repurchased after the leaks resulted in 3+ unsuccessful dealer repair trips. GM acknowledged the issue, and didn't put up much of a fight for the buybacks in those cases.
Here, the dealers need to get schooled quickly from GM by looking into their service bulletins for descriptions and fix details, and/or get in touch with their GM help and try to get the leaks fixed. If not, and it's tried multiple times, may be time for a buyback.