If you have this quest in your mission log then you will just keep seeding it out to other online players if you host the game.
With the added 4 DLCs there is a total of 216 missions. This is excluding "Talk to Tannis" and "Keep Your Insides Inside", two glitched missions cut from the game but are occasionally bugged to appear.
the 'Talk to Tannis' quest is not the same as "Get Some Answers" and the 'Keep Your Insides Inside' the similar quest would be "Fix'er Upper". But doing those missions will not fix this.
don't join strangers public games with your best character use a second character or just host, if your character has it you might want to start a new game, with a new Character.
here is a bunch of old talk from the archived forums