Happened to me on UA in C on IAD-MUC some years ago.
Push back on time and we were off to get in line with the departing aircraft...
10-15 minutes of waiting in queue later the captain announces that the crew noticed that we had not loaded some 75 meals, so we head back to a different gate.
15-20minutes of meal loading begins and we take on more fuel.
Lead Aunty FA mentions later that this happened all the time.