My experience was the opposite of yours at MPM. Check-in for business class took 30 minutes. There was only one person handling check-in for business. Economy was a disaster. A QR rep came over and moved the barrier from an economy line to allow two check-in agents for business and almost caused a riot. People were screaming at him and after about 5 minutes he moved it back.

There was no one at security so that was quick but immigration took about another 30 minutes. The entire area past the radiation scanner was full of people to the point that no more could fit.

Maputo itself was fine. The airport wasn't.