I still have the same problem on one of mine, and it has to do with the position of the canceling cam arm when the wheel is installed. From Flaming River's FAQ's:
Q: How do I set the cancelling cam to get my turn signals to operate correctly?

A: The canceling cam has two functions: First, it acts as a contact for the horn. Second, it cancels, or turns off, the turn signals as the steering wheel comes back to the straight-ahead position.
When the canceling cam is not clocked or timed correctly in the column, the turn signals will not cancel, or they will cancel too quickly. To properly clock or time the canceling cam, you should look at the top of the column like it's the face of a clock. On the canceling cam itself, there is a stem that sticks up approx 1-1/2”. Imagine this stem as the hour hand on a clock and place it at approximately the 10:30 position. This will ensure that the turn signals will cancel every time.
If you need additional help, please refer to this article or these videos — non-keyed columns or keyed columns.

Here's the link to their Tech Support Page - https://www.flamingriver.com/service...port/tech-tips