Loot despawning in iCC25

This week i've lead 4 ICC25 pugs and in 3 of them some loot despawned. It was just one piece in the first ones, but in the one I just did that died because of this, FOUR pieces of loot despawned. 2 heroic bracers, gloves and the sword from DBS.

It's heartbreaking because I lead a lot of these every week and now people think i'm robbing them of their gear.

Does anyone know what is causing this? I noticed this time that right when we switched back to NM from HC i had 4 holes in the loot stashed in my bags.

I know the simple answer is roll loot at each boss, which is what I'm going to have to do from now on, but it slows the raid down and also causes people to leave early.

This issue just started happening this week. Has anyone else had this problem when switching between nm/hc? Or when dying and running back into the instance?

To those of you who see this post that were in the raid, i'm truly sorry. I feel horrible that you guys missed out on the loot. I've opened tickets and made a forum post, I don't know what else I can do.

Huge issue, let's hope it's going to get addressed relatively soon.
*bump*