I'm sorry if this has been brought up before; the changelogs mentioned an inventory bug so maybe it has.
Anyway, I'm using Windows 7, and my inventory is extremely unreliable. Items will just disappear between battles, particularly ones I buy. I've lost the blood orb you can buy in the shop twice, as well as Temolo's lockpicks, one of the gold psy orbs, Ebon Raban's dropped equipment, and a number of replacement weapons. I think they might actually be changing into throwing axes? Most of my reserve inventory consists of throwing axes, but I don't remember buying or finding nearly so many. This seems to mostly affect reserve items. If I place items in my characters' inventories, they're usually okay... although I know I equipped Ebon Raban's kite shield so maybe not.
Items will also unequip themselves between missions sometimes, mainly Emma's and Sabrina's armor and helmets for some reason. In addition, sometimes they seem to be equipped but don't display the "E" symbol, and at least once I noticed that equipping an armor de-equipped a helmet (or at least removed the "E" symbol).
I'm sorry I can't give a log or more details, as I only even noticed something was off midway through the game, and I still usually don't notice until a few missions down the line. I'll try making before/after logs at the next shop I reach.