CD4050 Voltage leaks, what can I be doing wrong?
There are ESD diodes on the inputs connecting the input to Vcc.

You should add a resistor in the data line to allow the voltage to drop:







simulate this circuit &ndash; Schematic created using CircuitLab

You should then get 1.7v less the forward voltage of the ESD diode dropped across the resistor instead of heading up to the 3.3V rail.