[2022] Missions just disappearing?

Hey yall,

I'm new to the game. Just picked it up last night. Went through the tutorial, crashed my ship into the station a few times and then burned to death in a star because I couldn't figure out how to get far enough away from it to stop slowly turning myself into Cmdr Rotisserie. I grabbed a mission after to go kill a dude, because thats what you do after you catch a nice tan from literally the sun.

I plotted a course to the system he was in, flew out there and.... no dude. And my Transaction tab was empty too, no mission in there. Assumed I'm dumb and didn't actually pick up the mission I went and landed on a station and grabbed another combat mission because I'm a glutton for punishment and have watched far too much of The Expanse.

Left the station, double checked its in the Transaction tab, plotted course and zoomed out. Got into the other system, double checked - mission still there, flew out again to the system it was in and...nope mission gone.

Am I too dumb for this game? Where's my dudes to kill? Why do missions disappear from my journal as soon as I enter the system they are in?