Custom SQL thinks Connection is Read Only

When I connect directly to a table in my MySQL database, I can create a Question fine. I get data, I can do whatever I want with it. My user has full privs to read and write to the database.

However, when I create a new question and choose to add Custom SQL to create the question, I can’t do even a simple SELECT statement, I always get the following error:

Connection is read-only. Queries leading to data modification are not allowed

Here’s an example of a query that is getting this error. As you can see, there is nothing in this query that would lead to a data modification.

select billing_amount from member_deductible