What issues have been directly communicated by LWLG? I'm aware of speculated or inferred concerns but nothing thats been outright stated as a problem.
We dont know where or why the in house PIC development stopped, so theres potentially an obstacle there, but we dont know if it was a materials problem. Perhaps it's development was suspended due to the shift in the go to market strategy and unlrelated to a technical obstacle. Again, only speculating here.
I also dont believe whatever series of Perk (6?) they are using for the 400gb speed has completed reliability testing.
Correct me if I am wrong, but it sounds like wafer poling (recent patent application), reliability on Perk MK? (200gb) and ALD are all resolved at this time.