LG Front Loader FE Error - help with advanced diagnosis

My front loading washing machine has been giving me FE water overflowing errors, usually during the rinse cycle (wash cycle is fine). When it happens, usually the tub keeps filling up because cold water inlet valve doesn’t close so water keeps filling up the tub forever if unattended. In every other occasion, the inlet valve shuts off fine.

Good thing the drain pump kicks in so it doesn’t flood the wash room so there’s no issue or obstruction there and filter is clean, If I manually shut the water feed then the valve closes and pump is able to fully drain the tub, but by that point the alert has gone off and the wash cycle interrupted. I took it apart and replaced both hot and cold water valves assuming that was the issue, but I’m still getting the same FE error. I then started playing with the water level sensor and discovered diagnosis mode. The sensor seems to be working fine, the tube has no obstructions, water comes out of the tub into the hose, compressing the air (I think that’s how it works), and diagnosis mode shows me the frequency values going down to 17 (tub almost 50% full) and it rises to ~65 when empty. I don’t know how it knows to stop filling up and to close the inlet valve.

What else can I do to diagnose? Could there be an issue with the control board not recognizing the water sensor frequency? How can I train the control board to limit the tub water level to a certain number?