Vostro 5581 with WD19 - power button sometimes does not work

 Hello everyone,

I've recently bought WD19 docking station and everything seems to work with Vostro 5581 (including power delivery), except that in some cases the dock's power button does not always work.

When I connect dock to the laptop while it's running, it correctly detects laptop's power-on status by lighting the LED on the dock's power button, and I can use that power button as expected. I can even turn off the laptop completely and the dock's power button will let me turn it on again, so it's ok.

However, if I connect dock to the laptop when it's completely off, I'm unable to use the dock's power button to turn on the laptop. The dock's power button does not work even if I turn on the laptop afterwards (its LED indicator also remains off). The only way to make that power button work again is to unplug and plug again the USB-C connector while the laptop is running.

To me, it looks like the dock's power button only tries connecting to the laptop once, during plugging, and if it's done when the laptop is off then it won't work. What is strange to me is that connecting original power adapter to the laptop seems to help - when the laptop is off BUT it's original power adapter is plugged in, then I can plug in the dock and its power button will always work! As if the dock's power button could successfully initialize because USB-C port had power supply at the time of plugging.

I've got latest BIOS in laptop (25.10.2022) and also updated firmware in WD19. I also tried resetting BIOS to default settings.

Any ideas?