Incorrect date value: '0000-00-00 00:00:00' Solution....
Just as a FYI to anyone that is using Google Cloud SQL as their database for Vanilla make sure you set a database flag for SQL_Mode to include ALLOW_INVALID_DATES. You can do this from your Google Cloud Dashboard and look at your SQL instance and edit the flags.
Vanilla does a lot of calculations based on if a date is 0000-00-00 00:00:00 as a default and that is not a valid date so it will complain if you try to save a record that has this in it
Hope this helps someone else if you get the error "Cant insert because 0000-00-00 00:00:00 is not a valid date!"
I hope Vanilla will move to an epoch date field.. much simpler to use in calculations and you can use 0 as a default instead of NULLs as it would just be an integer field.