At this point, it is just a rumor. No idea if it is true or not. RxR on Seeking Alpha states that the initial 50 units were discarded immediately. After some pushing, he revealed that he does not believe it was due to a fault with the 50 units, but was due to the OEM requesting a new design.
The odd part is that these 50 units are for the pilot testing, which is mostly just an electrical test. Therefore, the pattern on the 50 units is not very important and the initial batch could easily be tested.
I believe that it is most likely (taking rumors into account) that the initial 50 units were fully tested and passed, but during the process a request for 50 different units was made so that the OEM could test them as well ('just to be sure') while they wait for the ODM to build out the pre-production units which will use units from the new batch (perhaps an additional 50 which are probably already printed/plated).
A poster on SA stated that the original 50 were discarded, looks like they sucked eh?
Then he stated UNXL had not provided a new ship date for the 50 replacements.
So here we sit.
HO HO HO HO HO HO HO