Hi,
Thanks for your update. As I understand it, you are observing this in signaltap. To help isolating any functional issue, it is recommended for you to create simple test design and run through Modelsim simulation to check on the behavior. Generally the Modelsim simulation behavior is similar to the hardware behavior for this IP. This would help to isolate any functional issue prior to hardware debugging. Please feel free to keep me posted on the simulation result.
Regarding the ast_sink_error, this is to indicate AVST violation to the IP. In normal cases, you can drive the ports with 2'b00.
Regarding the SOP/EOP, yes, you are right. For single channel, you do not need these ports. By default, when you select single channel, there will be no SOP/EOP ports.
Please let me know if there is any concern. Thank you.
Best regards,
Chee Pin