Stattik shiv disappeared when i bought Malmortius

Hello, i'm here to report a bug that happened once in howling abyss, i haven't tried to do it again. When i bought Malmortius, my Stattik shiv disappeared (I didn't sell it and I haven't been refunded any gold) just after I left the shop as shown on the video.

It's kinda disappointing to suddenly lose 2600 gold but it wasn't enought to stop me from carrying :P