The scouting mission seen in Darth Vader: Dark Lord of the Sith 22 that features multiple Mustafarians including Rrrn has been placed in 14 BBY because it follows shortly after the events of issues 20 and 21. Darth Vader could've only known the information he does in 18 about Tarkin if the novel Tarkin (which has been placed in 14 BBY) had already taken place. Issue 19 features the Second Sister and therefore must take place before Star Wars Jedi: Fallen Order (which has also been placed in 14 BBY since the game features her death. As the next three issues after issue 19 take place shortly after one another, it is safe to assume that Darth Vader: Dark Lord of the Sith 22 takes place in 14 BBY and therefore the Mustafarian scouting mission must also take place in 14 BBY.
I was told to do this before editing by another member as this is a status article. If this is incorrect, please tell me. --Mr Star Wars Amino Republic (talk) 15:45, February 13, 2020