For issues you find with the Switch and Console releases, please follow this link and give as much detail as possible. This is the speediest way to get info to Pipeworks and get a hotfix in the works.
1.4 will bring many changes to the PC version. We strongly advise making plans to back up your worlds and players prior to updating your game. More details here.
Begin your search for Journey's End information here and here. Please report bugs and issues for Journey's End here.
For issues you find with the Mobile 1.3 update, please follow this link and give as much detail as possible. This is the speediest way to get info to DR Studios to look at your issue. Also, some troubleshooting hints here.
Actually the lootflies are just predators that hunt their prey by disguising themselves as the loot, and there is only one real loot which cannot be destroyed unlike lootflies which are also empty aside from their organs.