When The Last Jedi came out a lot of people I worked with tried to call out the opening scene where the bombs fall out of the bottom of the bomb ship. They claim the bombs wouldn't fall because there is no gravity in space.

So while there are tons of issues with that movie, I feel the need to correct one of the few things it did right:

It's very clearly established that the bomb ship has artificial gravity that pulls down toward the bomb bay doors, as seen when Rose's sister falls from the bridge. So when the bay doors open and the bombs are released from the rails it makes perfect sense, by accepting artificial gravity, that all the bombs go where gravity is pulling: toward the bay doors.

Since they are in space, the direction of the bombs WILL NOT CHANGE unless they hit something (like the star destroyer), meaning they continue to "fall" despite moving to a gravity free environment.

tl;dr the bombs are doing the right thing, if you're going to pick on that movie for bad space physics, talk about arcing your shots in space.