Yes, Sandel has recently released a service bulletin addressing this issue. The problem has been traced to improper manufacturing tolerances used in the installation of a plastic polarizer in optical system, which does not meet published specifications. Sandel has stated that this problem does not present a flight safety concern and that it is only a cosmetic defect. This service bulletin applies to all serial numbers, shipped prior to August 24, 2009.

A glass polarizer has been designed as a replacement that does not the present the discoloration problem. This part can be retrofitted by the factory into any LED backlit unit.

Identical service bulletins on this problem have also been issued for the SA4550, SN4500 and the SN3500.