I cannot replicate your problem. I am using v7.8.6, with ? > Debug Info =
Notepad++ v7.8.6 (64-bit) Build time : Apr 21 2020 - 15:23:03 Path : C:\usr\local\apps\notepad++\notepad++.exe Admin mode : OFF Local Conf mode : ON OS Name : Windows 10 Enterprise (64-bit) OS Version : 1903 OS Build : 18362.720 Plugins : ComparePlugin.dll LuaScript.dll MarkdownViewerPlusPlus.dll mimeTools.dll NppConsole.dll NppConverter.dll NppEditorConfig.dll NppExec.dll NppExport.dll NppFTP.dll PreviewHTML.dll PythonScript.dll QuickText.dll XMLTools.dlldd7c7adf-9952-4528-a8d6-62d30249c6a4-image.png
I have Chrome as my default browser.
When I double-click on a link, it opens that link in Chrome.
Maybe you should try turning off Clickable Link Settings, exit all instances of Notepad++, run one instance of Notepad++, enable the setting again, and see if it works. Then exit and run again and make sure it still works.
If it doesn’t work for you, you will have to give us more information, including the ? menu Debug Info, like I showed above.