i found multiple bugs with the Dragon Backpack.

1. the strength it gives seems to be enormously high. i kill a other player with one hit, with anything in kind of weapon even with weapons, that just deal +1 damage. (only tested with tinkers construct. Reason below)
2. Almost no attack with any vanilla item seems to work. if i attack an other player or any mob. the attack almost never hits. (no knockback or damage.) but particle effects apear, like you are punching an other player in creative mode.
3. Fire Resistance works perfectly fine with fire. but in lava is sometimes a damage tick. but as i read you already fixed it for the upcomming version.
4. A general bug. it seems like the backpack doesn't drop, when the player dies on a half slab and dissapears, the same happend to me when i suffocated in a block under lava and when i was in the end and fought the chaos dragon (draconics evolution). to the last one, it might have been deleted or destroyed by the dragon. but maybe it is worth mensioning.
5. Also in general. it would be nice, if nightvision would get an other way to be applied to the player. or get a longer duration time while worn. so the flickering goes away. it is like you are on drugs, when you are in the nether and shaders are activated :3

Also i play on a private smp server. If you want the mod list installed on our server, i can send it to you as well.
If i can help, i do what i can.
I <3 your mod! Keep it going!

https://github.com/runescapejon/AdventureBackpack2/releases
Fixed

I recently died with a dragon backpack enchanted with Soul Bound. Ive died many many times with it, but for some reason this morning the backpack was gone. We're using the latest rev of the mod, on GTNH. Extra Utilities is installed but the packs never been in the grave. There was some slabs nearby but, I died about 5 blocks below them. Do bags share inventories per player? Can I get my stuff back via recrafting?