Similar problem for me - first unit delivered had the flickering filter LED issue, and then the same with the next unit sent to me. Through the retailer (Andertons in UK) Sequential asked me to do the following test:
Disconnect everything except power and headphones / Load any factory patch and turn the following parameters to max - tuned feedback amount & tuning, filter amp amount, amp amount / Create a basic patch by holding Transpose Up + Down + Latch, note the sound of the basic patch (you can record a video/audio clip for reference) / Leave the synth on for 10-20 minutes and see if the sounds change when you come back to it.
I did all this and the sound did change. Returned it to Andertons for repair.
I got it back really quickly, but the blinking issue is still there. I also did the test again with the same results.
Sadly, I've now got to the point where its refund time.