I followed your advice and took the plug out with pliers. That was a good decision. The goretex vent peeled of as soon as i touched it. Underneath i saw that there were moisture inside. I put the board outside to sun without plug and now there is water bubbling out of the hole.
This is interesting as i have not touched the plug at all since purchasing. So my original thought that ventplug is not correctly was right. The board has been in use couple of months and in water maybe 10-15 times. So i guess there was problem with plug since beginning. The top part maybe had beed broke already as i really didn't twist it at all and actually tried to unscrew it to chek if it is loose. I have other board with similar kind of plug and removed that one easily for comparison.
I weighted the board after first couple of sessions and weight was around 7,1kg bare board without straps. Today it weighted 7,15kg so there should not be that much water getting in, or then it sucked all that already on first sessions... The board is 5'4 95L, so pretty heavy for it size. But as i have read from forums, that is not uncommon.
Now i have to decide what to do. From previous experience i know that with retailer the warranty processes are not easy and take long so i'm hesitant to go that route. Maybe i let it dry for a week or so and check the things again.
However i'm thinkng could there be a bigger problem with goretex valves with 2022 skywing. As i read somewhere that there have been cases with cracks on sides of the board. This could point out that there has been water ingress and from that pressure build up in sun which would cause that? I'm not sure about this as i'm not expert but this came to mind.