This could induce a shimmy. So could an out of round or balance tire. I have owned 4 citabrias with a version of your tailwheel. I found a fix that worked for me. It would take an hour of typing to relate it to you.
Lets do it by phone.
I suggest you check for any play between the leaf sping attach point and the Scott tail wheel housing . In your case it may take two shims. Hope to hear from you. A high and low frequency spring is used to upset the frequency of the tail wheel. The lighter spring is used on the left side.