In case others find this same problem we found the cause and solution.
After update 5.19.0 the database had a new column added “email_type”. If the database was already created before the update the new column was not added. When trying to add a new template the error was column “email_type” was not found.
This SQL code will add the new column to the database
ALTER TABLE wp_ac_email_templates_lite
ADD COLUMN email_type VARCHAR(255);
I would also recommend adding the value of “abandoned_cart_email” to old templates in the database
