Data Type Error (Custom Data Field + Contribution Page Payment)

I created a custom data field called "bar Number" and set it to data type "integer, text field" and made it a non-required field.

I then added it to the contribution signup / renew page and when I try to process a payment, it says, "Sorry. A non-recoverable error has occurred. One of parameters (value: ) is not of the type Integer."

I deleted the custom data field and recreated it as data type "alphanumeric, text field" and it worked fine.