This is an old known issue. The problem is that you have constant sustained winds and there is a bug in Wunderground Module for Weatherlink. With constant sustained winds the wind gust never resets to zero. Or maybe it has nothing to do with sustained winds or not. Still the problem is in your software. That's a software bug.
There is no fix with your current software. Because the latest version v1.15 of Wunderground module for Weatherlink is over 10 years old. I would call that using old software that is no longer supported. Others have this issue with your software. Regardless using such old software that is out dated is just not a good choice, when there are so many better choices. Over 10 years a very long time in computer software years.
Solution: Upload to Weather Underground by some other means. Maybe use VVP and run Weather Display so that you can keep running your Weatherlink software. That is just one solution. There are countless other solutions. You could get Meteobridge for example. Or you could run WeeWx on a Raspberry Pi. Etc etc...
For example here you see the same problem from back in 2011. But there are other examples of people with this issue with your software combination
https://www.wxforum.net/index.php?topic=12054.0Wunderground Uploader module for Weatherlink is terrible in many other ways. You should get off that software for many other reasons. No rapid fire for example is one other big shortfall.