Is It Impossible To have Two Rune Bows?

Either that, or a really nasty glitch nailed me. I had been using Insight with my bowazon. I ran into an incredibly kind ultra high level player who told me how important a Faith bow was to a bowazon, and just gave me the runes for Faith. I promptly inserted them into a bow I had saved for that purpose. When I took the Insight bow, and moved it to my personal stash, and placed the Faith bow in my bowazons hands, the Insight bow simply disappeared and was gone. Just like that. And I really wanted to pass on that Insight bow to my merc, and now, it's just gone. Some of those were not at all easy runes to get, not to mention the bow to put them in.

Are you sure you did not misplace it into your cube? Or maybe you misclicked and it droped to the Ground instead of moving it into your stash.

Personally have never ran into this kind of a "bug" if it is a bug. But you can very easily misplace an item just like KIWI mentioned above.

It very likely had dropped to the Ground or gone into your inventory / stash somewhere.
Items wont just disappear and mercs cant wear multiple weapons on top of each other.

check your w,
second weapon solt