pm_device_action_run for UART causes GPIOs to switch states

Question

SDK: 2.6.1

I needed to add a single wire support to our device recently and I did that by using two pins TX/RX shorted and UART. It works, but current consumption sky rockets because of the UART. After some googling I decided that putting uart to suspended state should be the correct thing to do to fix that.

// single wire communication is done
const struct device* const dev = DEVICE_DT_GET(DT_NODELABEL(uart1));
...
int err = pm_device_action_run(dev, on ? PM_DEVICE_ACTION_RESUME : PM_DEVICE_ACTION_SUSPEND);
...

And it does. But then I noticed that when I call this API some seemingly unrelated GPIOs switch state. Why on earth is that and what can I do about it?

This is my pin device tree

&pinctrl {
    ...
	uart1_default: uart1_default {
		group1 {
			psels = <NRF_PSEL(UART_RX, 0, 0)>;
			bias-pull-up;
		};
		group2 {
			psels = <NRF_PSEL(UART_TX, 0, 3)>;
			/* max. 5mA drive strength: */
			/*nordic,drive-mode = <NRF_DRIVE_H0D1>;*/
		};
	};
};

&arduino_serial {
	status = "okay";

	w1_0: w1-zephyr-serial-0 {
		compatible = "zephyr,w1-serial";
		#address-cells = <1>;
		#size-cells = <0>;
		status = "okay";

		ds18b20 {
			compatible = "maxim,ds18b20";
			family-code = <0x28>;
			resolution = <12>;
			status = "okay";
		};
	};
};

And this is what I do somewhere before calling the PM API. GPIO is set correctly and stays set until about 2 minutes later when serial is put to suspended this GPIO also switches state

#define ENABLE_GAS_PIN      28
...
gpio_dev = DEVICE_DT_GET(DT_NODELABEL(gpio0));
err = gpio_pin_configure(gpio_dev, ENABLE_GAS_PIN, GPIO_OUTPUT_LOW | GPIO_ACTIVE_HIGH);
...
err = gpio_pin_set(gpio_dev, ENABLE_GAS_PIN, 1);

I found this old post. Someone had a similar problem but there is no solution devzone.nordicsemi.com/.../how-to-enable-disable-the-uart-with-ncs-zephyr