This already happens with conventional antivirus. I think the key selling point of AI-powered antivirus is that it doesn't need to be told about new malware - it will recognize them without requiring updates.
The fatal flaw with this approach seems to be:
malware makers are not “wooden dummies” -- they fight back and can come up with clever tricks that are easy to implement and could completely confuse the AI
If the malware makers have access to the AV software, then they can keep trying different things until it passes. Suddenly, your AI-powered AV software is now no better than conventional AV software - once again, requiring patches before it's able to recognize new malware.