SN74HC125: voltage drop

Dear team

The customer fed ~3.3V to SN74HC125PWR as its supply voltage. According to datasheet, the V_OH should really close to its V_CC. However, we only got ~3.1V for the V_OH by measurement.

We have tried to disconnect the circuit for this buffer output and leave the output pin floating and checked the voltage level on the floating pin. It can be considered as the test condition I_OH = -20uA, am I right?

Please kindly advise that what would cause the voltage drop on this SN74HC125PWR buffer output.

Many thanks

Denny