ATMs dispensing incorrect amounts, long queues

Today I used a Standard Bank ATM, and instead of R1,000, only R900 was dispensed. R1,000 was still subtracted from the account.

This is NOT the first time it has happened. The last time, the ATM was again R100 short, and I had to go inside the branch to ask for my money back. In a Standard Bank branch, the queues can sometimes be up to 30 people long, meaning hours of waiting. They were able to confirm that the machine dispensed too few notes, meaning that their system was already aware that the "error" took place. Were they hoping I would not notice? How many people daily do not notice when the Standard Bank ATM gives too few notes?