there are many items in GW2 that are, either right from the start or after you equipped them, no longer salvageable.
an example: if you buy the level 80 vigil heavy armor, that armor is not salvageable. Means, once you equipped the expensive runes in it, you can not get those runes back, except with using transmutation stones (lvl 80 ofc).
what i would like to see is an information on those armors telling me that i am not able to salvage.