yes it is - but only with an expert salvage kit. it is not 100% guaranteed. I salaved my knights armor to get the runes for my FoW armor and 4 out of 5 salvaged runes, 1 salvaged steel ingots.
It's not a bug, it's designed to potentially fail. You have a 100% chance of salvaging a rune from rune containing from monster armor, but it's lower on player armor.