Getting saved after disconnecting

Hi all.
Is this normal way of the game or some sort of bug ? Is there any way to avoid this in the future ?
example - doing VoA25 , getting disconnected mid fight, logging back ingame, but obviously i am outside of dungeon , leaving the group then getting saved in that dungeon whilist not inside of dungeon nor in raid group. ( i believe even if lets say i would remain in the raid group after kill , go inside , i wouldnt be allowed to roll by game mechanics because i was not there when boss was killed , or am i wrong ? )
I tried searching for this , but couldnt find any specifics about this.
Ill attach a screenshot of the chat log to make it easier to understand.
https://imgur.com/a/PLDxczo

That's how it works. If you're there at the start of a boss encounter, which you admittedly were, your player ID was already logged in the save. Since they killed the boss, you are then saved. That's the way it's intended to act. Only thing you can do is try not to loose connection in raids. It's also clearly on your side of the connection that's the issue since you were the only one to DC. Only way to avoid it is not to disconnect...look into your ISP or network traffic if it's a continuous issue