I noticed some of my dropped items were disappearing very quickly after I had dropped them on the floor. Since I can't bank, often I drop herbs, bars, gems etc on the floor and pick them back up shortly after. I did some quick testing and found out there is a bug.
The time it takes for an item on the floor to despawn is 60 seconds, this is accurate. However, if u drop an item, pick it up after 30 seconds, and drop the same item on the floor again, it'll despawn in +/- 30 seconds. Instead of resetting the despawn timer back to 0 sec, it picks up from the last time it had spent on the floor and goes on from there. I did another test where I dropped an item and every 10 seconds I'd pick it up and drop it again. After the 6th time the item despawned after only 10 sec!
This explains why I've been losing items from the floor
Please look into this :))