GPIO17 odd behavior in ESP32 WROOM32

[Mark81]

I have a custom board with a WROOM32. GPIO17 if used as digital output.
Sometimes, especially at power up, the high-level voltage on this pin is limited to about 2V, even with no load. A reset restore back the normal behavior.

I see in the pins_arduino.h file that is assigned to ETH_CLK_MODE:

#define ETH_CLK_MODE ETH_CLOCK_GPIO17_OUT

but I'm not using the Ethernet module.
From the eth_clock_mode_t enum I see I can choose among:

ETH_CLOCK_GPIO0_IN, ETH_CLOCK_GPIO0_OUT, ETH_CLOCK_GPIO16_OUT, ETH_CLOCK_GPIO17_OUT

but before go for a blind try, I would like to understand what does this setting actually do and if it can really be the root cause of the issue - given that I don't use Ethernet. I have 4 boards, and I see this on all of them.

[horace]

never observed such a problem - I have often used GPIO17 as Serial1 Tx signal
how did you test it? e.g. simple program such as

void setup() {
  pinMode(17, OUTPUT);
  digitalWrite(17, HIGH);
}

void loop() {}

always gives me 3.3volts

can you give details of the specific ESP32 module you are using?

[Mark81]

The p/n is: ESP32-WROOM-32D-N16.
I will try again with such a simple test program, just to be double sure.
Then I'll come back with the results.