See the schematic below for the circuit. On the input to the buffer, there is a 0V - 3V3 UART, working exactly as it should. On the output, I'd expect a 0v to 1V8 UART. But I'm getting a 1V8 always high.
It's not a dead chip, as the same problem persists over multiple PCBs (10) - there are no shorts, the resistance values are correct and the supply rails are stable. For testing the output of the buffer is not connected to the downstream device.
What is going on?
The markings on the IC: