Sajuuk:
I measured the Vout for all outputs and I get 3.10 - 3.20 V (@ 3.2 ~ 3.3V input) so as far as the measurement went I didn't notice any voltage drop.
So... is there something that I'm missing ?
You must have been measuring the output with little or no load. Try measuring the output with the motor connected, and measure it directly across the motor terminals (i.e. between the two H-bridge outputs).
Running a motor above its nominal voltage under light load will not harm it. What you need to avoid is prolonged running with the motor stalled or under heavy load, because this will burn out the motor or the H-bridge.