While following a tutorial by BlenderGuru, I ran into an issue where only half of the sprinkles were selected (as shown below).
I really don't know what could be causing this because I followed the tutorial step for step, and did exactly what the tutorial said. If I make any change to the sprinkle object, like add a material, they all get effected, but if I do something like apply random colors to the sprinkles, only the selected half get effected. I have my model provided below if you need it.
The tutorial: https://www.youtube.com/watch?v=jNmnPXY9UQA