Currently in an OSRS instance, your items won't de-spawn for 30 minutes. That includes loot drops and physically dropped items. On Alora the de-spawn timer is the same as outside of the instance. I always find myself losing loot and food killing bosses like Zulrah, Kraken, Vorkath, and Hydra because I always forget the de-spawn timer is a lot shorter than I'm used to on OSRS.
I suggest the item de-spawn timers in instances be increased to at or above OSRS times. It's not a huge issue, just something I've noticed while on the bossing grind.