Latest update to LibreWolf changed it's user agent string and it's causing websites to freak out. For example amazon will default you to a mobile website and Youtube music is having issues. To make matters worse if you try to download an extension to change the user agent string, it won't let you and tell you to download Firefox. You'll need to manually override the user agent string by going into about:config. You'll need to add general.useragent.override string into config.
Here is how you can do that:
https://www.whatismybrowser.com/guides/how-to-change-your-user-agent/firefox
I changed my user agent string to following and problem went away.
Mozilla/5.0 (X11; Linux x86_64; rv:138.0) Gecko/20100101 Firefox/138.0
EDIT: Looks like 138.0.1-2 has been released. User agent string has been changed back and all is well. You should now delete the general.useragent.override
Thank you ๐