Here are a few things you can try to fix the issue: 1)Update Firefox to the latest version: Outdated versions of Firefox may have bugs or compatibility issues that can cause audio delay when skipping. Updating to the latest version can help fix these issues. 2)Check for and disable any conflicting extensions: Extensions can sometimes cause conflicts with each other or with the browser itself, causing audio delay when skipping. Try disabling any extensions that you think may be causing the problem, or try using Firefox in Safe Mode (which disables all extensions) to see if an extension is the cause. 3)Reset Firefox: If none of the above steps help, you can try resetting Firefox to its default state. This will reset your settings and remove any extensions, themes, or other customizations you've made. 4)Check your computer's hardware and software: The audio delay when skipping may be caused by an issue with your computer's hardware or software. For example, if your computer's processor or RAM is low, it may not be able to keep up with the audio and video streams on YouTube. Similarly, if you have a lot of programs running in the background, they may be competing for resources and causing audio delay. 5)Check your internet connection: A slow or unstable internet connection can also cause audio delay when skipping on YouTube. Make sure you have a strong and stable connection to the internet. I hope the above suggestions would be of help :)