Possible causes for deterioration of PE-based prints in contrast to prints made on classic paper:
-) the deterioration of plain PE due to UV-light
-) un unwanted catalytic effect of the TiO2 within the PE on this
-) the absence of a baryta-/paper-sink for forming and migrating salts
This does not mean that it will happen, but these are the critical issues discussed in the past. There are preventive means against all three.