The other day I did several master writs including three for the enchanting station. Started out with zero glyphs in inventory. Crafted them and turned them all in. I received the writ vouchers and gold for completing them. Was finished with that character, logged out without checking inventory. The next day when going to break down the glyph received from doing daily writs, I noticed that there were also three glyphs created by that character within their inventory. These glyphs were the ones made for the master writs. It seems that my glyphs were not wanted after all.

I have since decon'd them. But thought I'd share what happened in case it is a known issue or something that needs looking into.