I have not seen this happen and I don't see anything in the Silkscreen Generator setup that would allow this. I would check your testpoint cell and make sure you don't have anything on the "Silkscreen Reference Designator" layer
this are to little information. Which version do you use?
Where do you want create silkscreen (pcb or gerber)? How do you create your Testpoint?
In PCB you can switch on /off the testpoint RefDes in display control.