Many people enjoying Red Dead Redemption 2 have noticed the sudden disappearance of several gang members from the main camp. Sadie, John, Abigail, and Jack will all go missing after a certain point early on in the game, leaving players concerned they weren't able to play missions given by these characters.
The bug is so prominent that Rockstar has released an article on its support page. The developer says it is "aware of the issue" and that it's currently working towards a fix, which will be included in the next patch for the game. It also highlights what is triggering the problem. If you die during the mission 'Polite Society, Valentine Style' in Chapter 2 and use the 'Retry Checkpoint' option, the aforementioned characters will disappear from camp -- unless they have a mission for you.
For now, the advice given to avoid the bug is to complete the mission with no failures, or load a save from before you failed it. Fortunately, at the start of Chapter 4, all characters will return to camp, so you could either carry on until then, wait for the patch to appear, or attempt the Chapter 2 mission again.
Have you noticed this bug in your time with Red Dead Redemption 2? Are you way past that point in the story, or will you attempt to bypass the issue by playing the bug-causing mission again? Sit down by the campfire in the comments below.