Field name length truncated to 20 chars makes insert queries fail

I'm sorry if this is an old bug. I'm reporting it here since I didn't find it on the issue queue.

If I name an extra field by using a name greater in length than 20 characters (for example, ucxf_fecha_nacimiento, 21 chars), the name gets truncated to just 20 characters (ucxf_fecha_nacimient). This truncated name is also obviously reflected in an ubercart order object $order->extra_fields['ucxf_fecha_nacimient'].

Though this could be a normal behavior, the columns in the database table get named by using the original long name I used in the first place, making the field column name, on the uc_extra_fields_values table be ucxf_fecha_nacimiento_billing. This obviously makes the queries to fail since the module is trying to write values to a non-existent column named ucxf_fecha_nacimient_billing.

Since I created this field, the module ceased to write new rows to the table.