analogRead() disables pullups... is this intentional?

Official Hardware Nano Family Nano 33 IoT
1

Hi there,

I just ran into a strange problem with analogRead(), which seems
to ignore the requested internal pullup resistors:

analogReadResolution( 12 );
pinMode( A0, INPUT_PULLUP );
value = analogRead( A0 );

returns values about 1500 when the pins is not connected.
In other words, the pullup is NOT active. BTW, I also tried

analogReadResolution( 12 );
pinMode( A0, INPUT );
digitalWrite( A0, HIGH ); // alternative way to enable pullup
value = analogRead( A0 );

but the result is the same.

I guess this is due to a bug in cores/arduino/wiring_analog.c
because analogRead() internally calls:

pinPeripheral( pin, PIO_ANALOG )

which in turn disconnects the pullups from the pin PMUX... (it sets
the pins PORT_PINCFG_PMUXEN bit, which according to Fig 22-3 in
the SAMD21G18 datasheet disconnects the pullup/pulldown logic).

For now, I changed it like this:

// pinPeripheral( pin, PIO_ANALOG )
pinPeripheral( pin, PIO_INPUT_PULLUP )

which seems to work. But I am nowhere sure that this is the correct fix.
Anyway, the behaviour seems to be the same for all SAMD controllers:
am I the first one trying to read analog values with internal pullups enabled?

Best, Norman