Large voltage drop across source terminal
The circuit you have built is called a source follower. It is also known as a common drain amplifier.
In a source follower, the source voltage can never rise higher than the gate voltage.  The source will always be lower than the gate voltage.
You have a gate voltage of 1V above ground.  The source can never be higher than 1V above ground.
You also have a series resistor between the drain and the 3.3V rail.  That reduces the current that can flow through the MOSFET.
The MOSFET source should be at 1V, but with the 1k resistor in series and the load of the &quot;ENABLE&quot; pin, the source voltage drops a bit to just 0.7V.
The simplest solution is this:



simulate this circuit &ndash; Schematic created using CircuitLab

R3 holds the gate of the MOSFET high, keeping EN_DC23 low.
A high (1V) on VCCINT causes Q1 to conduct, pulling the gate of M1 low and allowing EN-DC23 to be pulled up by R1.

Whatever EN_DC3 is, it might already have a pull up.  Then you could remove R1.